Cut the celloidin into thin strips, or, if it be hard, break it up in a clean mortar, and dissolve in the above mixture of alcohol and ether. When dissolved, this forms the collodion.

THE IODIZER

is composed of:

When the salts are dissolved, filter and add to the collodion.

The filtering is best done by placing a pledget of cotton-wool in the neck of a glass funnel and passing the iodizer through it. To prevent evaporation, lay a glass plate over the funnel.

The iodizer being added to the collodion, shake them up thoroughly and allow to stand for a week to settle, then decant into convenient bottles; this collodion is ready for use in a week, but will improve with age up to six months, after which time it should be mixed with new.

When coating plates with collodion, it is not a wise plan to pour the surplus from the plate back into the bottle from which it was poured. Pour it into another, kept handy for the purpose, the contents of which, at the end of the day’s work, empty into the stock bottle after such a quantity as is sufficient for next day’s consumption has been decanted into the pourer.

The best bottle from which to pour the collodion upon the plate is the tall capped bottle sold by the dealers as collodion pourers. {12}

To make it, dissolve 6 ounces of nitrate of silver in 10 ounces of water, then add 10 drops of collodion, and shake up well; then add 70 ounces of water, and let it stand all night; then filter through a pledget of cotton-wool packed loosely in the neck of a glass funnel, into a clean bottle or jug; then add 1 drachm of nitric acid and let stand all night before trying. Such bottle or jug, and also the glass funnel, must be kept solely for use with the silver bath.

The bath holder may be an upright vessel of the ordinary pattern, with a dipper with which to lower the plate into the solution; or it may be a flat dish with a cover to keep out light and dust, using a silver hook to lift the plate from the solution; if the former shape be chosen, let the dipper be of glass, porcelain, silver wire, or of wood soaked in melted paraffine, but on no account of ebonite, as such a dipper will cause spots, and derange the bath sooner or later.

If a flat dish be used, the best form is of wood lined with asphaltum, hanging on a cradle, the lower end being a well to hold the solution; in this form of bath the plate, after sensitizing, is drained thoroughly before taking it out. This is a great convenience, as not only is silver solution saved, but the dark slide will last much longer.

The bath solution made up as above will be the right strength for work, but as every plate sensitized therein, takes away its modicum of silver, after a certain time it must be strengthened, as it is essential for the production of good work that the solution be kept at a proper strength. The best way of doing this is to add a drachm or two of saturated solution of nitrate of silver, after each day’s work has been done, and if the solution be worked in a flat bath, it will be as well to pour it into a jug and filter it before using again; with an upright holder, this filtering will only require to be done about once or twice a week, as any particles of dust, etc., subside and have not the same chance of falling upon the film as in a flat bath; but the addition of the silver solution should be made, and the solution well stirred up with the dipper.

In course of time a silver bath will become contaminated with organic matter from various causes, and can also be supersaturated with ether and alcohol—with iodo-bromo or nitrate of zinc, and will either refuse to work, or only {13} yield imperfect films and thin images. In such cases the best plan will be to take 20 ounces of the solution, dilute it with clean water 60 ounces, filter, and add 6 ounces of nitrate of silver, and again filter, when a new bath will be the result.

The silver in the rejected portion of the old bath should be precipitated as a chloride, by the addition of a solution of common salt, the precipitate dried and sent to a refiner, together with the ashes of the filtering papers and blotting-paper used to drain the plates upon, or to wipe the backs of the plates after leaving the bath and before putting them into the dark slide.

The silver solution named above, is suitable for negatives of subjects in line, but for the production of negatives with delicate half tones, such as portraits, landscapes, or of the many subjects which are photographed direct, then it will be necessary to provide another bath solution, made and managed in the same way, but only containing sufficient nitric acid to just redden litmus paper, as a bath gives the finest half-tones when nearly neutral, or only slightly acid. It should be remembered that the deepest shadows are represented by clear glass in the negative, to insure which would be impossible with the silver solution inclining ever so slightly toward alkalinity.

The nitrate of silver bath may be made up with distilled water, if pure—that is, if the water is bona fide distilled and not merely from waste steam; if this cannot be guaranteed, the best plan will be to get a gallon of tap water, dissolve in it one ounce of nitrate of silver, then add saturated solution of bicarbonate of soda, until an alkaline reaction to litmus paper takes place, then place the lot in white glass bottles, and expose to the action of light for three or four days. During that time the solution will, first of all, turn black, and then will gradually become quite clear, the organic matter—which if not removed, would have caused trouble—falling in a black mass to the bottom.

Now filter the purified water and use it for compounding the nitrate of silver bath, but do not use it for any other purpose.

The strength of a nitrate of silver bath, for line work, should be thirty grains of nitrate of silver to each ounce of water, and should not be allowed to fall below twenty-five; and for half-tone negatives, nitrate of silver should be thirty-five, and not lower than thirty grains to the ounce.

Be sure to keep all funnels, bottles, and dishes used for the silver bath, separate and distinct from all others, and never use them for any other purpose. {14}

The directions given above for making a bath solution for line negatives, will, if carried out carefully and cleanly, at once yield a solution giving good negatives. After the bath has been mixed, either with distilled water, ordinary tap water (in iron districts tap water should not be used), or water that has been sunned and filtered, as soon as the bulk has been made up to the eighty ounces, the solution should be put away all night before it is tried, then in the morning filter it carefully through a pledget of cotton-wool stuffed loosely in the neck of a perfectly clean funnel, into a perfectly clean bottle or jug, which must be kept entirely for use of the silver solution. When the bath solution has been filtered it should be perfectly clear; if it is at all cloudy or turbid, the filtration must be repeated.

When the solution is perfectly clear and bright, pour sufficient into a perfectly clean porcelain, glass, or papier-machÉ dish, then take a clean plate (polished, or albumenized) and coat it with collodion; close the door of the dark-room, and when the film of collodion is perfectly set, raise one end of the dish containing the silver solution, place one edge of the collodionized plate against the bottom of the upper edge of the dish, then drop the plate upon the bottom of the dish, and at the same time lower the dish; by this means the silver solution will flow in an even wave over the surface of the collodionized plate; now place the cover on the dish so as to exclude light and dust, and allow the plate to remain in the solution for five minutes, then with a silver hook lift the plate from the solution, and allow it to drain (remember that no light must get into the dark-room except what is filtered through either two thicknesses of golden fabric, or one of canary medium); when the plate has drained so that no solution drips from it, place it into the carrier of the dark slide; then close the dark slide and let it remain there for five minutes, at the end of which time remove the plate to the sink, and flood it with sufficient developer (page 17) to just cover the film; keep this solution flowing, to and fro, over the {15} plate for the space of two minutes, then wash it under the tap until the surface is no longer greasy; then apply the fixing or clearing solution (page 17) until the whole of the yellow bromo-iodide is dissolved away; again wash, and take the plate into the daylight.

Now comes the test; if the film is perfectly transparent, and clear as the glass itself, the bath is all right; but if there is the slightest deposit (which can be removed by lightly rubbing the finger along the surface of the film), then the solution will require the addition of a little nitric acid. After this stir it well, and after a rest of an hour or two try again, repeat the addition of the nitric acid, and try a plate; repeat until the film, after developing, washing, and fixing, is perfectly clear, and free from deposit and fog.

The bath is now in proper working order, and if reinforced after each day’s work with a sufficient quantity of saturated solution of nitrate of silver (filtered), kept free from contamination with other chemicals, and carefully filtered occasionally, it will remain in good working order for at least six months, and then may be renewed by treating as directed on page 12.

It will sometimes happen, notwithstanding that extreme care and cleanliness is exercised in the management of the bath, that it will not work properly, and the reason why cannot easily be discovered. In such a case, steps must be taken to put the solution into working order.

In the case of rectifying a disordered bath, there are many methods of procedure, but the simplest, and, as a rule, the most certain method, is to render the solution alkaline by the addition of liquor ammonia, adding the ammonia a little at a time; then, after well shaking, test it with red litmus paper and continue the addition of ammonia until the red litmus paper is turned blue. In this alkaline condition the solution should be poured into a large flat dish, and exposed to the action of the sun. That will speedily reduce and throw down in the form of a black precipitate, any organic matter that may be in the bath, and at the same time the heat of the sun will cause evaporation of the ether and alcohol left in the solution by the collodion plates.

The bath solution should be exposed to the sun for two or three days, or until such time as suffices to render the solution clear, and the precipitate entirely separated out. But this cannot take place unless the solution is decidedly alkaline, the presence of acid stopping the action of light.

Do not be in a hurry about doctoring a bath solution (in fact, it will be far best to have two solutions, one in use and one either resting or being doctored), but give the light plenty of time to reduce the organic matter, and also to {16} volatilize the ether and alcohol; then filter the solution through filtering paper (don’t use blotting-paper), as if it is attempted to filter through a pledget of cotton-wool the fine precipitate of organic matter quickly clogs the wool and stops the filtering.

The doctored solution being filtered, test it with a piece of perfectly fresh, blue litmus paper, and add nitric acid, drop by drop—shaking well between the additions of acid—until the blue litmus paper just turns red. Do not add acid sufficient to make the litmus turn violently red, unless the bath is for line negatives, as a bath for half-tone negatives must be only just acid, whereas a bath for line work must contain more acid.

If the color of the litmus paper shows that the alkali has been neutralized, a plate is collodionized, then immersed in the bath for five minutes, then drained, and placed in the dark slide, or in a dark box for five minutes, then flooded with the iron developer (page 17); if, upon the application of this the film should turn black, add more nitric acid, stir up thoroughly, then try again, repeating the trials until, upon fixing the plate with the solution of cyanide of potassium, the film of collodion is left upon the glass plate as clear as it was before it was immersed in the silver bath.

A little above here it is stated that less nitric acid is required in the bath for half-tone negatives than for line work, and the question may well be asked where may the line be drawn? The reply is that, for half-tone work, a piece of blue litmus paper should, upon immersion into the solution, turn red very slowly, but when the bath is required for line negatives the blue litmus may at once indicate the presence of acid.

After a bath solution has been renovated in the above manner, it should be tested for strength, either by the volumetric method (by preference), or by means of the ordinary argentometer sold by the dealers, and, if, after testing, the strength is shown to be too great, dilute with a sufficiency of sunned water (page 13); and if not sufficiently strong, add crystals of nitrate of silver to make up the strength to thirty or thirty-five grains per ounce.

A bath solution renovated as above, will generally be found to work cleaner, and yield brighter negatives than a new solution, and it will also, if carefully used, last longer; but it must be kept up to a proper working strength by the occasional addition of a little of a saturated solution of nitrate of silver.

The fact that the strength of the silver solution has got too low is shown by the presence of semi-opaque, fantastic markings near the thick edge of the collodion film, and also in conjunction with the presence of organic matter in {17} the deposition under the surface of the film of an extremely fine sand-like deposit, which, in the fixed negative, develops into myriads of pinholes in the densest portions of the image.

But bear in mind that, unless there are crystals left in the solution after each addition of hot water, it will not be saturated; therefore, before taking the solution into use, be sure there are undissolved crystals in the jar.

For use, take of

In the above solution, the alcohol is added to enable the developer to readily assimilate with the sensitive film, and the quantity requisite varies with the age of the silver bath, or, to be more correct, with the quantity of plates sensitized therein. At first, little or no alcohol will be required, but after a number of plates have been sensitized the developer refuses to flow evenly, and seems disposed to run over the edges of the plate; this is a sign that more alcohol is required, and when more has been added the developer will flow evenly as before; but when 80 ounces of developer require over 4 ounces of alcohol to make it flow, it is a pretty sure sign that the bath wants remaking.

The developer is applied to the plate after exposure, from a straight-lipped cup, or glass measure, which should be kept for the exclusive use of this solution, as the mixture of any of the other solutions with it will at once counteract its working power. {18}

This solution is highly poisonous, both in solution and vapor, so it ought to be kept in an upright holder, the plate being lowered into the solution on a dipper; keep the solution well covered up, so as to prevent evaporation as much as possible.

After being in use a short time this solution will become weak and should be strengthened by the addition in the evening of a lump or two of cyanide and then stirred up with the dipper in the morning; the negative must not be left in this solution too long or the density of the film will be impaired, but must be removed and well washed directly all the yellow iodide has been dissolved.

THE INTENSIFIER.

Solution No. 1 is best kept in an upright holder, as if kept in a flat dish there is always the danger of cutting the skin with the glass plate and getting the mercurial poison into the system.

No. 2 is kept in a well-stoppered bottle and only sufficient for each plate withdrawn as required.

Another method of intensifying, for those who object to the use of mercury, is to bleach the negative in a solution of

dissolve and filter. {19}

When the plate is bleached, wash it thoroughly under the tap, taking care that the edges and corners of the film as well as the centre are washed, then flood it with a sufficient quantity of

which will at once turn the film an intense black; again wash, and flood with the nitric acid solution, and again wash; then the negative is allowed to dry.

This method of intensifying is cheaper than the other, and if the washes of acid between and after the other two solutions are carefully done, and the stench of the sulphide is not objected to, then there is little or no difference in the results; but if the acid washes are omitted or (and) the sulphide has not been kept corked, and is consequently not fresh, then there is great danger of a brown stain upon the lines, which is more or less fatal to getting a good print on zinc.

For half-tone negatives, instead of fixing or clearing with the cyanide of potassium, the developer is washed off directly, and then they are intensified at once by the application of a mixture of pyrogallic acid, citric acid, and nitrate of silver, as follows:

is added. Then the mixture is poured over the film, and rocked to and fro for a short time; the intensifier is then returned to the cup, the negative held up to the light, and examined, and if not intense enough, the intensifier is again applied. Great care is requisite at this stage, as if the process be carried on too {20} far the negative will be too intense, and will either be spoiled, or take an abnormal time to print; practice and observation are the only guides to success. The grand rules for half-tone negatives are, collodion free from dust, the glass plate clean, the bath at its full strength and in good working order, proper time allowed the plate in the sensitizing bath, well drained, afterward a good exposure, develop until all details are out, then wash thoroughly, intensify with judgment, wash well, fix, and again well wash, and then, but never till then, open the dark-room door and examine your new negative by daylight.

In making the collodion, soak the celloidin in the ether for about twelve hours before adding the alcohol; be sure the ether is at least 0.725 specific gravity, and that the alcohol is very clean, and free from gum. After mixing the collodion and iodizer, shake up well, but do not do this before decanting. Always decant sufficient for next day’s use, into the bottle used for pouring, over night, so that it gets a chance to settle, and allows the air-bubbles to escape.

Keep the collodion in as cool a place as possible, and in decanting it be very careful to do it away from fire, or lighted gas or paraffine, especially where flame is below the bottle, as ether vapor does not rise, but falls.

In hot weather and during long exposures, wet plates are very prone to have a peculiar stain upon them, called oyster-shell markings, the remedies for which are careful draining before putting them into the slide, and covering the bottom of the carrier with clean filtering paper, so that the silver solution, on draining down, is absorbed by the bibulous paper instead of going back up the plate by capillary attraction.

In hot weather the back of the plate, when put into the dark slide, should be covered with a wet piece of red blotting paper, or orange calico, but not white; a wet cloth laid in the camera will also tend to keep the plate moist. These precautions, however, are not required unless the exposure is likely to exceed a quarter of an hour.

But the best plan of all is to use a water varnish, made by dissolving half an ounce of borax in a quart of boiling water, then adding a few pieces at a time (stirring meanwhile), one pound of ordinary shellac; if the quantity of borax named does not suffice to make all the shellac dissolve, add more, a grain at a time, until the shellac is dissolved; then add half an ounce of white sugar, cool and filter it.

When the negative is washed for the last time, allow it to drain, then flood with the above solution, and let it dry. This will be found a quicker, cleaner, and more satisfactory method of protecting the delicate film than with the spirit varnish.

As a good and suitable negative is the foundation of success in the subsequent processes, so is a properly cleaned glass plate the foundation of a successful negative; unless the glass is chemically clean, the collodion film will either be stained or marked, or it will split off in drying, therefore care and attention are requisite; even in preparing a piece of glass for the reception of the film of collodion care is especially requisite, as the want of it cannot be seen until after all the operations, therefore the labor and time are not thrown away.

There are two methods of cleaning the glass plate: one quite mechanical; the other is a mixture of the mechanical and the chemical. Both are good. The second is perhaps the best, as it is simple and more certain.

In the first method the glass, when new, merely requires polishing with clean wash leather kept for this purpose.

The best way of doing this is on a flat board 24 by 18 inches, or thereabouts, {22} covered with good American oil-cloth, glazed side out. A plate laid upon this will not slip about when being polished.

Both sides and edges of the plate must be well cleaned, as one of the most prolific causes of derangement of the silver bath is from organic matter introduced by imperfectly cleaned glass plates.

One side of the plate, if gently rubbed with the thumb nail, will be found smoother than the other, and is the suitable side for the support of the collodion film; this side is polished with the leather until, upon breathing gently upon it, the film of moisture is quite free from marks or streaks, not only in the centre but at the sides and corners.

It is absolutely necessary that the plate be chemically clean all over, else the film of collodion, upon drying, will split, and the negative be spoilt.

When the plate is clean, an edging of India-rubber dissolved in benzole, about an eighth of an inch wide, is run all round the edge, by means of a small camel’s-hair brush tied to a stick, the end of the stick being level with the point of the brush. The stick acts as a guard against the brush going too far from the edge.

In the second method, the new glass plate is soaked an hour or two in a mixture of 5 ounces of common spirits of salt (hydrochloric acid) in 80 ounces of water. After both sides of the plate are rubbed with a rag, and well washed under the tap, it is put in a dish of clean water. When all the plates have been so treated, they are taken out singly, again well rubbed on both sides with another rag, and well washed; then the smoothest side having been selected, it is twice flooded with a mixture of albumen and water, draining the surplus into the sink each time of flooding. The plate is then placed upon a rack to drain and dry; the drying should be effected in a current of hot air freed from all dust.

The albumen mixture is composed of the white of one egg well beaten, then diluted with 40 ounces of water and ten drops of liquor ammonia added, and again beaten. It must then be very carefully filtered through cotton-wool, and used as above.

In placing the albumenized plates upon the drying rack, care must be taken to face the coated sides all one way, as when dry there is nothing to indicate to the eye which is the back and which the front.

The albumenized plates, when dry, should have the backs cleaned with a cloth or a leather before using, so as to clear away any albumen which may have adhered during coating. {23}

Albumenized plates stored in a dry place will keep good for months, and do not require any edging with India-rubber, as the most horny collodion film will not split off an albumenized plate.

Glass plates that have been used, and not varnished, are freed from the films by being immersed in a mixture of hydrochloric acid and water for a few hours, then washed under the tap, well rubbed with a rag, and put into clean water, from which they are taken singly and coated with albumen; or they may be allowed to dry, and are then polished by means of the wash leather.

Negatives that have been varnished are cleaned by first immersing in a hot solution of common washing soda until the film comes off, then wash them under the tap, rubbing well with a rag, then immerse them in the acid solution so as to neutralize the alkali. Finally they may be treated as above.

The films that are removed from the glass plates must not be thrown away, but should be carefully collected, dried, and sent to a refiner with the other silver waste; a good plan for saving these films, and at the same time keeping the acid and soda solutions clear of them, is to filter each solution occasionally through an old felt hat suspended conveniently over the tanks, using one for each of the tanks.

The polishing of the glass plate must not be done in the dark-room, or the crop of comets, spots, etc., upon the negatives will be exasperating in the extreme; let this operation be conducted in a clean, quiet corner of the studio, where no other operation will disturb, and where the fluff from dusters and leathers will not interfere with anything else.

The chemicals being prepared, they must be placed in the dark-room; the collodion bottle should be placed on a convenient shelf close to the door, and on a handy peg hang a broad camel’s-or badger-hair brush, for dusting the clean plate just previous to coating it with collodion; the brush must not be used for anything else upon any pretence whatever. The silver bath must be kept, both in use and out of use, in some convenient corner, where there is no risk of getting any other chemical splashed into it. For a bath holder a deep 15 by 12 porcelain or papier machÉ dish, with a wooden or stout cardboard lid, should be provided, and this dish must always be thoroughly washed, and wiped dry with a clean damp leather (kept for the purpose), both before use and after pouring the silver solution back into its bottle or jug. Or, if the upright form be preferred, be sure and have it large enough.

The developer should be placed on a shelf, on the right of the sink, the developing cup close by.

The fixing or clearing solution should be kept in an upright bath of glass, porcelain, or ebonite.

The intensifier No. 1 may be kept in a flat dish, or in an upright holder, at discretion; but if in a flat dish, the solution should be poured back into its bottle, after each day’s work.

Keep the intensifier No. 2 in a stoppered bottle close to the sink.

The water varnish also is kept in a bottle or jug.

On a shelf close to the collodion, the polished or albumenized plates may be stacked, with the clean or prepared side facing the wall.

A pneumatic holder for attaching to the back of the plate during the operation of coating with collodion will be found very handy.

Of course, it is thoroughly understood that there is a sink in the dark-room, and a good water supply is indispensable.

Then, again, the window through which the light is transmitted, must be {25} covered with a non-actinic medium, such as two thicknesses of golden fabric, or one of canary medium; do not stint the amount of light, but have as much as possible, so long as it is non-actinic.

No arbitrary plan for the dark-room need be followed, but the novice will find the annexed plan useful to him in con­tri­ving for himself. It is self-ex­plan­a­tory.

Everything being in read­iness, we will now pro­ceed to make a line neg­a­tive, reserving a des­crip­tion of half-tone work to follow.

To begin: wash the bath holder thoroughly, and wipe it dry, then pour into it sufficient silver solution to make the depth about half an inch; dust the inside of the cover, and put it over the dish; now take a clean glass plate, if it be polished, see that it is edged with India-rubber, and if albumenized, be sure and clean the back—and attach it to a pneumatic holder; then with a broad camel’s-or badger-hair brush (kept for this purpose only) remove any particles of dust, back and front; now hold the plate in a horizontal position and pour upon it, toward the right hand corner furthest away from the body, a little more collodion than it is judged will be sufficient to cover it; let the collodion run to the corner, then incline the plate to the left, and the collodion will run into the upper left-hand corner. Now by inclining the plate toward the body the collodion will flow into the lower left-hand corner, and thence it is guided into the funnel placed in the bottle prepared for its reception; during the time that this surplus is draining, the plate must be gently rocked sideways, so that the lines formed by the collodion, in draining, are merged, leaving the film quite homogeneous. As soon as the collodion ceases to drip, release the plate from the pneumatic {26} holder, and touch the lower ridge of the collodion; if it is quite set, close the door of the dark-room, remove the lid from the bath holder, then—holding the plate in the left hand—with the right hand raise the end of the bath holder, as far as is possible without risking any of the silver solution running over the end of the dish resting on the bench; now lay the plate (with the collodion side up) on the bottom of the dish, then drop the plate into the solution, and, at the same time, lower the end of the dish held up by the right hand, which will cause the silver solution to flow in one even wave over the collodionized surface. This operation must be done with dexterity, as if the silver solution does not flow in an even wave the film will be marked, and, in the case of a half-tone negative, the image will be spoilt. Therefore, it is necessary to see that the plate and dish are lowered simultaneously, so that the solution goes over the collodion film in one steady wave. If the upright bath holder be used, the plate is placed upon the ledge of the dipper, and lowered slowly and steadily into the solution.

The plate will require an immersion of about three minutes for proper sensitizing, and this interval—the bath being covered up to prevent the access of white light—may be utilized to give the final adjustment to the camera, and to see that the drawing or print to be copied is properly in focus.

Use a medium diaphragm in the lens for focussing, and examine the image all over before deciding that it is sharp. Focus by preference about halfway between the centre of the picture and the edges, and then, after moving the rack to and fro until the proper sharpness is obtained, take out the diaphragm and substitute the smallest sent out with the lens; or if the picture to be taken be small and from a large original, then the second, or third, smallest diaphragm may be used.

Now remove the focussing screen from the camera (note that the ground side of the glass has been next the lens) and place the cap upon the lens; close the door of the dark-room, open the dark slide, see that the proper carrier is in it, then raise the plate from the bath slowly, using a silver-wire hook for the purpose. If the solution flows evenly over the film, the plate is ready; but if, on the contrary, the solution flows greasy, then again lower the plate and rock the dish gently for a minute or two. The film being fully sensitized, the plate is carefully lifted out of the solution, both hands holding the plate in such a manner as to avoid touching the film; allow the solution to drain from the plate as much as possible, then lean the plate against the wall, the lower end resting upon a pad of clean blotting-paper, so as to catch any further draining; {27} now with a pad of blotting-paper or papier-joseph wipe the back of the plate as dry as possible; this will prevent stains, and keep the dark slide from rotting by the action of the silver solution.

The plate being drained, lay a piece of thin filtering paper in each lower corner of the carrier, so that the plate will rest upon the filtering paper, which will catch any further drainings from the film, and be a safeguard against stains.

Now lay the plate face down in the carrier of the dark slide, close the door, and fasten it.

The dark slide is now carried to the camera, and inserted in the grooves previously occupied by the focussing screen, taking care that the sliding shutter is next the inside of the camera; when pushed quite home, cover the back with the focussing cloth; pull out the shutter, when the plate is ready for the exposure.

The time of exposure will vary very much with the time of the year, and with the amount of light falling upon the object being photographed. The exact time can be found out only by actual practice, but the operator, in time, by observation, will be able to guess it pretty correctly.

In taking the cap off the lens, be sure that the camera is not shaken, else the picture will be spoilt.

The exposure being made, close the sliding shutter, remove the slide to the dark-room, and close the door; lay the dark slide (with sliding shutter down) upon the bench, open the back shutter, and, placing the pneumatic holder in the centre of the plate, lift it out of the carrier.

Take the plate to the sink, and holding it face up, in the left hand, take the developing cup in the right, and, with a quick motion, pour over the plate sufficient developer to cover the whole film; the developer must go all over the film in one even wave, for any hesitation in this will result in a stain; pour upon the film only sufficient to cover it, and be careful to spill as little as possible into the sink, or else the image will be thin, on account of the absence of free silver washed off by the wave of developer.

Now rock the plate gently, so as to keep the developer flowing to and fro over the film (but keep it there, don’t spill it off) and the image will soon appear, faint at first, but growing gradually darker, the black lines of the drawing being white and the white paper black. If the development be continued too long the lines will eventually be veiled; therefore, as soon as the finest details are out and well defined, place the plate under the tap and allow {28} the water to well sluice the film all over; as soon as it is properly washed, which can be seen by the water flowing evenly over, without greasy looking lines, hold the negative up in front of the window, and examine for spots or stains. If there be any present that at all interfere with the picture, at once reject the negative, placing it in a pan filled with water, to be washed off at leisure. Then start afresh.

The negative being satisfactory, give it another rinse under the tap, and place it in the cyanide bath, where the unaltered iodide will speedily be dissolved. Then it is withdrawn, and well washed under the tap. Whilst the water is washing over the front, rub the back with the fingers or a sponge, and then turn the plate over and allow the water to wash the back also. It is now ready for immersion in the intensifier No. 1, where it remains until the film is bleached almost white. Then it is thoroughly washed, drained, and flooded with a small quantity of intensifier No. 2, which will at once turn the film to an intense black, or if the action does not penetrate through to the back of the film, continue the application until it does; again wash, then place the negative on a rack to drain. When the water ceases to drip, flood the plate twice with the filtered water varnish. Then place the negative on the rack to dry. When dry, it is ready for printing on zinc. The negative may be varnished with a benzole varnish, sold by the dealers under the name of positive or ferrotype varnish. Negative varnish may be used, but unless very thin it is apt to be sticky and render the negative easily marked by the heavy pressure it is subjected to in the printing-frame.

Now lay the finished negative face down upon a piece of clean white paper, when, if it is a good one, all the details of the original will show through, clearly and distinctly; but if any of the details are missing or veiled over, the negative will not do, and another must be made.

This process does not always work satisfactorily, but with care and cleanliness no serious fault should arise.

Sometimes the bath may give what are called foggy images, which are indicated by a veil over the lines. These can often be wiped off with a pledget of cotton-wool. The addition of half a drachm of nitric acid to the eighty ounces of bath solution, thorough mixing, and a rest for a few hours, will end this difficulty. If the dark-room window be not of the proper color, fog will ensue; therefore, the non-photographic experimentalist had better call in the aid of a professional photographer in case of any difficulty in getting clear negatives.

Wilson’s Photographics will be a profitable investment, as it was published {29} before the advent of dry-plate photography, when the wet process reigned supreme.

At the end of each day’s work the silver solution should be carefully poured into the jug or bottle, and allowed to stand all night; then in the morning, just before using, it should be filtered. The dish also must be carefully washed out and put away in a corner where it has no chance of being soiled.

Such are the manipulations necessary for the production of a negative from a line subject—i. e., a drawing in black and white, in which the whole of the picture is obtained by means of lines, or stipple, or by cross hatching. Flat washes of color not being permissible, all effects of half tones, etc., are obtained by lines, either thicker, or thinner, or closer, or further apart. Such a negative is available for printing from, direct upon zinc, in either albumen or in bitumen, for etching into relief, or for printing from as a lithograph.

For line work negatives for printing upon zinc, for etching, or for transfers to stone, ordinary gelatine dry plates are not useful, as it is almost impossible to get that freedom from veil over the lines that it is absolutely necessary to have; here the wet collodion is best as it is simplest, easiest, and cheapest. {30} Still there are times when the most ardent wet-plate worker is obliged to confess that the process has its shortcomings, most especially in dull weather, when it is necessary, to get the result required, to give exposures from thirty to sixty minutes; then, what with the plate drying and the want of pluck from the bad light, it is impossible to get a result suitable for the work. In this case the plate called the “Process” plate is a great boon. It is fairly rapid, and gives intense negatives, without veil on the lines.

For making transparencies same size of original negatives, the best plan is to place a large sheet of white paper in front of the copying camera, and rack the lens out of focus, taking care that the white sheet of paper is sufficient to illuminate the full size of the plate. Then in the dark-room place the negative in the carrier of the dark slide, film side up, and carefully dust the surface (also seeing that the back of the negative is clean) with a clean camel’s-hair brush; dust also the film of a gelatine dry plate, and place it face down upon the negative, close the slide, and insert it into the grooves of the camera and expose to the light reflected through the lens from the white sheet of paper for from five to twenty seconds, according to the density of the negative and the intensity of the light; close the lens and the shutter, and remove it into the dark-room for development.

By exposing a plate in this manner there is a far better chance of getting absolute contact between the two plates, as the rays of light are parallel.

For making transparencies for printing upon copper-plates, first of all make a grained negative the proper size, then when this is varnished and touched up, make from it as above a transparency upon a gelatine chloride dry plate, by which process it is more certain to get a suitable result for the process than on a gelatine bromide dry plate.

No formula will be given here for developing these gelatine chloride plates as each packet has full instructions for development which must be followed implicitly.

For developing gelatine bromide dry plates for negatives, or for transparencies, the following, a modification of the Ilford formula, will be found better than using formula where the ammonia and bromide are mixed together.

For a normal exposure equal parts of these are mixed just before using, and for an uncertain exposure begin with two parts of No. 1, one part of water, and one part of No. 2.

This transparent positive may be made on an ordinary gelatine-bromide plate, or on a gelatine-chloride plate, and then from the transparent positive a negative is made by transmitted light (in the enlarging camera), either the same size, reduced or enlarged in size; or instead of using this class of transparency, by far the finest results can be got by making the transparency in carbon tissue, which can be used for both transmitted light, for enlarging or reduction in size, and it can also be used for contact printing, when the reproduced and reversed negative is required to be the same size as the original.

On page 29 directions are given for the manipulations when gelatine dry plates are used, so here we will confine ourselves to the production of negatives from the carbon transparency. First of all, procure some carbon transparency tissue, ready sensitized, cut this into sizes at least half an inch larger all round than the negative, then cut a brown paper mask to fit all round the negative, and to protect the margin of tissue from the action of light; this acts as a safe edge to the tissue, enabling it to adhere to the glass support during the operation of development. If it is only intended to reproduce a portion of the {32} original negative, the safe edge may be made by putting the mask just round that portion of the image, but if the whole of the negative is required, put it in a printing frame with a plate glass front, fix the brown paper mask outside the negative, then place the sensitive carbon tissue the black side next the negative film, and put in the backing, and back, and fasten it up. Next expose it to the light for four or five times the time requisite to get an ordinary silver print.

The carbon tissue having been exposed to light for the proper time, it is taken into the dark-room, the edges are turned up so as to form a dish, and pinned upon a small board; it is now coated with thin plain collodion, the surplus being poured into a bottle kept for the purpose, and the board gently rocked to and fro, so as to prevent the collodion running in ridges, or streaks. Now allow the collodion to dry, then place the coated and exposed tissue in clean cold water until it is quite limp, then slide underneath it a gelatinized glass plate a little larger all round than the tissue, bring the gelatinized surface of the glass plate and the collodionized surface of exposed tissue in contact under the water, taking great care not to abrade the collodion; then lift the two out and lay the glass down upon a bench, and cover it over with a piece of thin India-rubber, or mackintosh, or oil-cloth. Hold the cover firmly on the bench with the left hand; with the right use a strong squeegee vigorously. That will expel all the water from between the two surfaces (collodion on the tissue, and gelatine on the glass), and so bring them into absolute contact; now remove the cover, lift the plate and examine the tissue through the glass, and if there are no air-bells between the two surfaces the operation has been successful; but if air-bells are present, at once plunge the plate into cold water, strip off the tissue, and try again, but be careful to be quick about it, or there is a risk of the tissue absorbing too much water, in which case great difficulty will be experienced in getting it to lie flat upon the gelatinized glass.

The gelatinized plate upon which the exposed and collodionized tissue is mounted is prepared as follows: Glass plates free from scratches and stains, are placed in a weak mixture of hydrochloric acid and water, and rubbed with a clean rag until free from grease and dirt; they are then washed under the tap, and whilst wet are covered with:

Soak the gelatine in the cold water until it is soft, then melt at gentle heat, add the bichromate, and when dissolved, filter, and coat the cleaned plate two or three times, throwing the surplus away each time of coating; now stand the coated plate on a rack to dry. Any quantity of these plates may be prepared at a time, and used when required. When all the batch has been coated, the rack may be removed into a warm corner, free from dust, until the plates are dry, then expose the plates to the light for at least twenty minutes, when they are ready for use for mounting the exposed and collodionized transparency tissue upon.

After the tissue is mounted upon the glass plate, it is allowed to stand a few minutes, then it is placed in a dish containing hot water (100°F.), and as soon as the tissue compound shows signs of dissolving by exuding from under the paper, lift the paper away, then rock the dish, and, if necessary, add more hot water; then raise the plate and gently lave it with the hot water, until the whole of the soluble pigmented gelatine is washed away, leaving a transparent positive on the glass, which merely requires washing under the cold water tap, and drying, to be finished. Now examine it closely, and if it contains the whole of the details in the negative, and is free from dust spots, it may be put away to dry, but if underexposed, or overexposed, or marred by spots not in the original, then another must be done; but if care is taken to dust the surface of the tissue, and the film of the negative with a camel’s-hair brush before printing, and before collodionizing, and also to see that both the collodion and the gelatine mixture are properly filtered, and that the water in which the coated and exposed tissue is soaked is free from dirt, then there will be no difficulty in getting a perfect transparency.

The transparency being obtained, if it is desired to make a negative larger or smaller than the original, the transparency is placed in the enlarging camera with the carbon film inside, and the negative made the requisite size, either on a dry plate or on a wet collodion plate.

If a negative the same size is required, the transparency is placed face up in the carrier of the dark slide, and the surface dusted; then take a dry plate, and having also dusted its film, place it face down in contact with the transparency, then close the dark slide and remove it to the camera, which should be previously adjusted opposite a large sheet of white paper; now put in the dark slide, draw the shutter, and expose to the sheet of paper, and develop as directed on page 30.

By exposing in this manner, instead of direct to the light (day or gas), the {34} rays projected through the lens fall upon the dry plate quite parallel, so securing sharp negatives.

In making reversed negatives for collographic printing when wet collodion is used, it is not absolutely necessary to use the mirror, as they may be made upon polished glass (i. e., not albumenized) dried, then coated with gelatine, again dried, and stripped.

Some brands of dry plates can also be stripped, by first of all, after drying, coating them with India-rubber solution, then with collodion, and soaking in dilute fluoric acid; but great care and patience must be exercised, the preliminary trials being made upon negatives of no particular value.

When it is intended to strip the film, the glass plate must be polished, not albumenized, and after the negative is dried, strips of thick paper are pasted along the four sides of the negative, with starch, or a solution of gum tragacanth; the negative is then placed on a levelling stand and a sufficient quantity of the following warm solution of gelatine is poured upon the plate (which should be slightly warmed first) and spread all over it by means of a glass rod:

Soak the gelatine in the water until soft, melt by gentle heat, then strain through two or three thicknesses of fine muslin, and pour upon the plate, using three ounces for a plate 12 × 10; more or less, in proportion for different sizes. The plate must be allowed to stay upon the levelling stand until the gelatine has quite set, then put it on a rack to dry, in a current of cold air, for if heat be used the gelatine will melt.

When the gelatine is quite dry, pass the blade of a penknife all around underneath the strips of thick paper, when the negative film may be lifted away from the plate.

In this condition the negative may be stored away without risk of being broken, the only condition being, it must be kept free from dampness. {35}

Another plan of stripping is to coat the dry negative with a thick solution of India-rubber in benzole, and allow it to dry on a levelling stand; then coat with a thick plain collodion, to which a few drops of castor oil have been added. When the collodion film is quite dry, place the plate in a dish of clean water, strip off the film from the glass, then place the film between sheets of clean blotting-paper to dry, or it may be allowed to dry on the plate.

Old collodion negatives that have been varnished may be stripped, but it is rather a risky operation, and should never be attempted until a really good carbon transparency has first been obtained.

The first step will be to remove the varnish, which is effected by soaking the plate in

until all the varnish is removed, then rinse in alcohol, wash well under the tap, dry, paste slips of brown paper around the margin, and finally level and cover with the warm gelatine, dry and strip.

The silver surface of the mirror requires great care and attention to preserve its lustre. If tarnished, it will make the exposure in the camera longer, besides which, the cost of resilvering is too great to allow of the surface being spoiled through carelessness. {36}

At the end of each day’s work, remove the mirror from the box and warm it in front of the fire (not over a gas flame) just slightly, then wrap it carefully in a piece of fine velvet, which has also been previously warmed, then wrap it up in a piece of India-rubber or macintosh cloth, and put it in an air-tight box; by doing this, the mirror, if well silvered at first, will last for a year or two.

If the surface should become tarnished, get a square of very fine chamois leather, and place in the centre a pellet of cotton-wool; then gather up the leather and tie the wool in the centre, making a small globe about an inch and a half in diameter; now warm the mirror, and after dipping the leather globe into fine rouge, proceed to polish gently with a quick circular motion, using little or no pressure—take care in doing this that the mirror, the leather, and the rouge are quite dry, else the silver coat will come away—verb sap.

In purchasing a mirror be sure and get it large enough to take the cone of rays from the lens it has to be used with; for a lens three inches in diameter, the plane mirror should measure about 8× 3¹?/?₂ inches.

The box to hold this mirror should be made square at the side, fitting into the rabbet of the camera front, so that when objects are to be photographed that will do better lying on the ground than when fixed against the wall, the mirror can be placed to look down upon the object.

For silvering the glass, one cannot do better than to quote the directions for working Common’s process given by Major Waterhouse in the Photographic News.

“The solutions recommended by Mr. Common are three:

The above quantities are suitable for 250 square inches, consequently, an ordinary copy mirror 8 × 6 would require rather more than two ounces of each solution, and other sizes in proportion.

The caustic potash and distilled water must be quite pure. Ordinary caustic potash will not answer at all. The best to use is known as pure by alcohol.

The glass surface to be silvered is carefully cleaned with strong nitric acid, applied, as recommended by Mr. Browning, with a Buckle’s brush, then well {37} washed in clean water, and after rinsing with distilled water, laid, face downward, in a dish of distilled water until wanted.

Before cleaning the glass, it will be necessary to arrange for supporting it face downward in the depositing dish, so that the surface to be silvered may be quite horizontal, and just below the level of the fluid, which should be about half an inch above the bottom of the dish.

I have generally used a large cork, about four inches in diameter, cemented to the back of the plate, and fitted with three strings, by which it could be suspended in a level position and adjusted to any height by winding the string over a roller placed at a convenient height above the dish. When this arrangement is not available, I fix on the back of the plate two ordinary wide-mouthed bottle corks of equal thickness, in the positions shown in the figure, and to these corks attach thin slips of bamboo running transversely across the plate, and of sufficient length to rest on the sides of the dish, thus:

The slips of bamboo give the arrangement a certain amount of spring, by which the height of the plate can easily be regulated, by putting on weights until the surface of the plate is just below the level of the fluid in the dish.

To prepare the silvering solution: A sufficient quantity of the silver solution, No. 1 (two ounces), is put into a perfectly clean glass. Ammonia is dropped in until the precipitate first formed is just redissolved. The same quantity of potash solution, No. 2, as of silver is now mixed in, and the precipitate again dissolved by ammonia. A little more silver solution is then added to produce a distinct turbidity, and distilled water to make up the quantity necessary to fill the depositing dish to about three-eighths or half an inch, and the mixture is then filtered through cotton into another clean glass vessel.

The same quantity (two ounces), of filtered solution of glucose, No. 3, as was taken of silver and potash, is now mixed in, and the whole is poured into a depositing dish (which should preferably be of glass, well cleaned with nitric acid).

The glass plate is then taken out of the distilled water and laid face downward on the silvering solution, being supported, as before described, just above the surface, so that the solution does not cover its back.

Mr. Common places the requisite quantity of distilled water in the dish in {38} which the mirror has been remaining face downward, and then, having lifted the mirror up, pours in the undiluted silvering solution, together with the glucose solution, stirs well together, and then carefully lowers the mirror again into the dish.

Almost immediately after the immersion of the plate, the silvering action begins, and, if things are going on well, a brilliant reflecting surface will be seen at the back of the plate, and in forty minutes, or even less, a good deposit of silver will be obtained. It is usually recommended to stop the action as soon as the silvering fluid appears clear and free from turbidity, but it is not always easy to see this.

After silvering, the plate is well washed, finishing with distilled water, and dried off quickly. A slight cloudiness of the surface may appear, and must be removed by polishing before the mirror can be used. It is better to allow the mirror to remain a day or so before polishing, in order to harden the coating.

To polish the plate, it should be slightly warmed, and perfectly dry, and rubbed very gently in small circles with a piece of very soft and dry chamois leather, afterward using a little jewellers’ rouge.

Mirrors should always be kept in a dry place, and will require repolishing from time to time.

A suitable negative (the subject being in line, not half tone) having been obtained, the next stage toward producing a relief block is to make from that negative a print in ink upon a sheet of zinc. To do this a sheet of polished zinc is first of all subjected to the action of a solution of nitric acid, alum, and water. It is then thoroughly washed, placed in a machine called a whirler, then coated with a solution of albumen (white of egg) and bichromate of potash; this coat or film of bichromated albumen should be dried over a spirit lamp.

The negative is then placed, face uppermost, in a printing-frame, the coated side of the zinc in contact with the face of the negative. The negative is now exposed to the action of light.

The exposure being complete, the frame is taken into a room lighted by yellow light, gas, or lamp-light, the zinc plate is removed, and its surface covered with a thin film of transfer ink, by means of a type-printer’s roller; then the zinc plate is immersed in clean cold water and the image developed by gently rubbing it with a pledget of cotton-wool.

Lay the plate upon a board covered with muslin and polish with a “from-and-to” the body motion, not circular; do not use a great deal of pressure, the object being to get the plate highly polished with a perfectly smooth surface.

Plates that have been printed upon, and are not satisfactory, may be cleaned and repolished.

Plates that are scratched require polishing with emery cloth. Scratches interfere with the picture. {40}

To remove scratches, sprinkle the face of the plate with turpentine, then rub with a piece of FF emery cloth stretched over a carpenter’s cork-covered rubber. Use the same motion, to-and-fro, until all the turpentine has evaporated and the surface of the zinc is polished. If the scratches are removed, the plate is ready for use, but if not, then the operation must be repeated. If the scratches are too deep for emery cloth alone, first use a piece of fine pumice stone, followed by snake stone, pumice powder, rotten-stone, and rouge. Too much care cannot be taken with the zinc plate at this stage, for, after the block is etched, if it is discovered that the plate has not been properly polished, all will have to be done over again, entailing a loss of time, labor, and materials.

Remember, that no matter what polishing agent is used, the plate must be polished with a to-and-fro from the body motion, not a circular motion such as is usual in polishing metal.

This graining is done in a wooden tray, 24 inches by 18 by 6, lined with asphaltum or gutta percha and mounted upon rockers; it is quite necessary that the graining tray be of large size, as if only a little larger than the plate the returning wave of acid water will mark the edges of the zinc.

Into this tray pour a quart of clean water, and add one drachm of nitric acid and one ounce of a saturated solution of common alum. Place the plate in this, face up, and commence rocking it at once or else the acid will mark the surface, and it will require repolishing; rock slowly for five minutes, during which time the polished surface will give way to a fine matt, like fine frosted silver. Now remove the plate and rinse it under the tap, rubbing it gently with a fine sponge, or a pledget of cotton to remove the scum or deposit formed by the acid. The surface at this stage should be quite smooth; if it is at all rough, the acid is too strong, and the solution must be diluted with water; if the action of the acid is very slow, then a little more must be added; but it will only be necessary to add more alum when the plate is a bluish color instead of being a pearly gray.

A drop or two of acid will be required each time plates are to be grained.

In rubbing with sponge, or a pledget of cotton when under the tap, care {41} must be taken not to scratch the surface of the zinc, or else it will need repolishing.

Two pieces of wood, each half an inch thick, twelve inches long, nine inches wide at one end, and six inches at the other; upon the narrow end of one piece fix four screws, a piece of iron the shape of a ?, the top end of which is shaped to fit into the socket of a carpenter’s brace (which must have the centre handle revolving, not fixed); the cross piece must be flat, and pierced with four holes, countersunk to admit of stout screws.

Place the two pieces of wood together, the ? piece between the two, and with a piece of stout leather hinge the two together, nailing the leather not only on the outside, but upon the top also; now screw a narrow batten on each of the pieces, about an inch from the widest end, to keep the wood from warping.

Four inches from the top (the hinge being the top) bore a hole through both pieces, and pass through a couple of strong leather laces; by one end fix these on the outside of the cheek to which the iron ? is screwed, and on the outside of the other cheek, seven inches from the top, hinge a piece of wood (so as to fall toward the bottom) 5 inches by 2 by ¹?/?₂?; and in the centre of the batten screwed on to prevent warping, fix a broad-headed nail or a turn-button, over which the free end of the leather laces can be passed.

Now about half an inch from each end drive through the wood, six or eight wire nails one inch long in a line, and so that the points project on the inside of each cheek. Next fix the top of the iron into the socket of the brace and the whirler is ready for use.

To use this instrument, lay it upon the bench, raise the upper jaw, place the grained zinc behind the teeth (face out) close the jaw, and after seeing that the face of the zinc is close up to the teeth, tighten the shoe lace, pass it over the hinged piece (which is lying down close to the cheek), and around the batten with two or three turns, then pass it back and tie the loose ends around the iron shank at the top; then raise the hinged piece, which by straining on the {42} leather laces will cause the jaws to grip the zinc plate tight and hold it in position. (See Fig. 4.)

Now lift up the whirler from the bench, grasping the handle of the brace firmly in the right hand. Hold it at arm’s length, and by a series of quick jerks set the plate revolving. This will require a little patience to do evenly and rapidly, but with practice it will become quite easy.

The plate is coated twice, whirling it after each application of the sensitive mixture. The whirler is then laid upon the bench, and the hinge piece let down. This relaxes the strain upon the leather laces, and allows the jaw to be lifted and the plate removed.

An inverted revolving egg-beater may be made to serve for the same purpose.

For drying large plates, two or more of these stoves would be required, but it is very easy to extemporize a suitable arrangement, by laying a large pad of cotton saturated with spirits of wine in a tin dish, and setting it on fire; by this means a stove of any desired dimensions can be prepared quickly. To extinguish such a flame, cover it with a large sheet of zinc.

It must be borne in mind that the film on the zinc is now very sensitive to {43} light, therefore the preparation of the film must be done in a yellow light, as must also the operation of placing it in the printing-frame, inking up, and development; gas or lamp light may be used, as the film is not sensitive to artificial light of a low actinic power.

The front glass of the printing-frame must be kept perfectly clean, and especial care must be taken that no grit be upon either glass, inside the frame, or on the back of the negative, else the negative will be broken.

Johnson’s actinometer is very simple and handy; it consists of a cubical box with two lids, the inner one serving to press the paper in contact with the glass of the outer lid; the outer lid has a circular opening with a narrow rectangular strip in the centre transparent, the rest of the glass being covered with pigment the color assumed by the sensitive paper after exposure to the light. When the strip of sensitive paper inside has assumed this color, it is called one tint; the strip of paper is then pulled forward, and another portion, quite white is brought under the transparent portion of glass, and when the light has turned that the color of the pigment, that counts two tints, and so on. The paper used in the actinometer is ordinary albumenized paper.

The exposure of zinc in the printing-frame under a good line negative, will be about six or eight tints in diffused light, but in direct sunlight the exposure may be timed by the watch, a suitable line negative never requiring more than from three to five minutes. {44}

For this purpose we require a type-printer’s composition roller, mounted upon a litho stock. This roller must be perfectly smooth and cast in a solid mould, as the line along the side, formed by a split mould would render it useless for inking up a zinc plate. A roller eight inches long by five or six inches in diameter is a useful size. We also require an inking slab, a palette knife, a bottle of turpentine, with the cork cut so that the turpentine can be sprinkled out without having to remove the cork, a tin of transfer ink, and a linen cloth or two.

The inking slab may be made of smooth iron, or a suitable lithographic stone is good.

The negative being ready for printing, select a piece of zinc a little larger each way than the picture, polish, then grain, and after well washing it under the tap and gently rubbing it with a fine sponge, or a pledget of cotton-wool, place it in the whirler; again rinse under the tap, now invert the whirler and set it revolving; then examine the surface of the zinc and see that there is no dirt on the surface, but that it is quite smooth. If it is not, rinse it again under the tap, and rub it gently with the sponge, and again rinse. This should quite free the zinc from any deposit of dirt. Now whirl it so as to get rid of as much as possible of the water, then pour over the surface of the zinc sufficient to cover it, of the following solution (carefully filtered through cotton-wool):

Place the white of egg in a bottle containing a lot of small pieces of perfectly clean glass, then add the water and shake it well for a minute; then add the solution of bichromate and again shake it well. Now place a pledget of cotton-wool in the neck of a glass funnel, and pass a few ounces of clean water through (if this is not done, there will be difficulty in getting the albumen to filter); drain as much as possible of the water away, and then filter the albumen into a clean bottle; when all the solution has gone through, remove the cotton-wool from the funnel, which well wash, then recharge with a fresh pledget, pass some water through, and again filter the albumen solution through, this time into a ten ounce glass-measure, which is to be used for pouring from upon the zinc. The stem of the funnel should be long enough to reach the bottom of the glass measure, so that the formation of air-bubbles be avoided, which is impossible with albumen if the funnel is not below the surface of the filtrate.

Of this, pour over the zinc sufficient to well cover the surface, letting any surplus go into the sink; then set the whirler revolving, coat again, and {46} again whirl; now examine the surface, and if it is free from dust, spots, and air-bubbles, remove the zinc and dry it over the spirit stove. But if either air-bubbles or dust be present, wash them off under the tap, and begin again.

The film being dry, get the printing frame ready, see that the surface of the glass inside is quite clean and free from grit, as also the back of the negative, taking special care that the ridge of varnish which often forms at the bottom of the negative be removed, as the slightest inequality of surface will surely cause disaster directly the screws exert their pressure.

Do not lay the negative into the frame flat upon the glass, but slide it in from one side, so as to carry any dust away from the glass front of the printing frame.

The negative being in the frame, film side up, lay the coated zinc upon it, face down, judging the proper position and placing the zinc flat down upon the negative; now put a piece of brown paper over the back of the zinc, then place the back of the printing frame in place, fasten down the cross bars and apply the pressure screws, evenly and gently.

Do not screw one side tight before the other has been touched, but screw down so as to tighten all as evenly as possible.

Even pressure being applied, see that the front of the frame is clean, and then expose to direct sunlight for five minutes. Remove the frame to the dark-room, unfasten the cross bars and remove the zinc, taking great care to avoid scratching its film against the film of the negative.

After wiping the inking slab with clean linen place a piece of the transfer ink, about the size of a small bean, upon the upper corner, sprinkle this with a little turpentine, and mix them with the palette knife until they are of about the consistency of printing ink.

Now with the palette knife spread some of this mixture as far as possible over the inking slab, and then distribute it with the composition roller. Roll to and fro, across and diagonally, until there is a thin, even coating of ink all over the slab (not touching the corner where the ink was mixed with the turpentine) and upon the roller; if the mixture is too dry and refuses to spread, sprinkle on a little more turpentine, but do not use too much, else it will take a long time to evaporate.

The roller having a coat of rather moist ink spread evenly upon it, place the exposed zinc, face up, on a piece of clean white paper, and proceed to roll it briskly to and fro, using a moderate amount of pressure, until the whole of the turpentine has evaporated; it should leave a thin coat of ink with an even {47} matt surface, not thick enough to quite hide the yellow film of the sensitive albumen, as, if it does hide it, too much has been put on, and it will most likely smear in development.

If, after first applying the roller, the ink on the zinc seems likely to be too thick, at once wipe the roller dry, and then roll the zinc briskly until the coat of ink is perfectly even and the turpentine evaporated.

At this stage everything depends upon getting the coat of ink even. If there are patches of thick and patches of thin, sprinkle some turpentine upon the slab, quickly charge the roller, and roll up the zinc again, until the coat of ink is thin and even.

An even coat of ink being obtained, the zinc is laid in a tray containing clean cold water of a sufficient depth to well cover the surface. Now take a pledget of cotton-wool and rub the surface gently, when the ink covering the albumen protected from light by the black portions of the negative, will wash away, leaving the picture on the zinc in ink; if the finer details do not develop easily, continue the rubbing with the cotton-wool, but be careful not to rub so hard as to scratch the ink lines.

All details being developed, rinse the picture under the tap and put it away to dry, which at ordinary temperature will take but a few minutes.

The chances of failure in this portion of the process are, first of all, air bubbles and dust spots in the film. These will at once declare themselves. The remedy, is increased care and cleanliness.

If, upon development, some of the lines are missing, then the zinc and the negative have not been in actual contact, or if the finer lines wash away easily, then the exposure has not been long enough; whilst if it has been too long, either the finer details are covered up or the whole refuses to part with any ink.

A satisfactory print, showing all the lines of the original having been obtained, dry, by first blotting off the water, then by gentle heat, after which the zinc is ready for the etching room.

The process described in the previous chapter is most suitable for printing on zinc, for blocks that are not overburthened with fine lines, and is intended for rough printing; and also, when from want of sunlight, and the exigencies of business, the exposure has to be made by electric light; but when the subjects are very fine, and the blocks must be of the very best, it will be better to print the image in bitumen; then the first etching can be done without having to ink up previous to immersing in the acid bath (which must be done after developing the inked albumen image), so getting the sharpest possible results, and also securing better depth to close work than when the inking up has to be done before biting in.

Now the generally accepted idea of bitumen is, that it requires such a long exposure to light as to be practically useless, except for direct sun printing; but that only stands good where the bitumen is not prepared properly and where too thick a film is used upon the plate.

By preparing the bitumen as described below and taking care to have a very thin film of the sensitive bitumen upon the zinc plate, then the exposure either to sunlight or electric light is not more than double that of albumen.

There is one especial virtue in a bitumen film. If by chance too much exposure to light has been given, a prolonged immersion in the developing liquid (turpentine) will remedy the defect, whereas if an albumen image be over-exposed it is quite spoiled, and the work must be done again.

We are still upon the subject of line work, and the same class of negative desirable for printing on an albumen film is necessary for printing upon bitumen, viz., the lines must be clear glass without veil, and the rest of the negative must be sufficiently opaque to stop the passage of light.

The sensitive solution of bitumen is made by procuring a small quantity of photographic bitumen or asphaltum, and powdering it in a clean, dry mortar. Next take a clean and dry glass beaker, half filled with methylated ether, and pour into it the powdered bitumen, stirring with a glass rod for a few minutes; now cover the beaker with a piece of thin sheet India-rubber, and upon that {49} place a piece of plate glass, so as to make the vessel as nearly air-tight as possible. Allow to stand a few hours, then stir up again, and again allow to stand, this time all night. Then pour away the ether, draining the liquid as closely as possible, so as to get rid of all those constituents which are soluble in the ether. Now add some more fresh ether, stir thoroughly, and again allow to stand and settle, putting on the cover as before, so as to prevent evaporation. After again settling, the ether is poured off, and all liquid and semi-liquid matter carefully drained away. More ether is added, and the operation is repeated until the added ether, after standing all night, is nearly or quite colorless. The residue in the beaker is removed to a glass plate and spread out over its surface, so that any ether remaining may quickly evaporate. During this evaporation of the ether, the bitumen must be protected from the action of white light.

By thus purifying with ether we get rid of those constituents of the bitumen which are not sensitive to light, and thus we secure a film of bitumen sensitive to the action of light.

When the ether has evaporated, take of the residue half an ounce and dissolve it in pure benzole (free from water) fifteen ounces, allow it to stand all night, then filter it through filtering paper (placing a sheet of glass over the funnel to prevent evaporation). It will keep six months.

New zinc plates will require polishing first with rotten stone, and finishing with rouge, but plates that have been used should be first polished with fine emery cloth, followed by pumice powder, then by rotten stone, and finished with rouge, remembering that a circular motion must not be used.

If, after polishing, the surface is at all greasy, immerse it in the graining bath used for the albumenized plates, wash well and rub away the scum; then with a perfectly clean piece of blotting paper, remove the water from the surface and dry it over the spirit flame.

To coat a piece of zinc with bitumen, place it in the whirler, and when fixed in position, dust the surface with a clean camel’s-hair brush; then flow over it sufficient of the filtered bitumen solution in benzole, then lower the whirler and set it in motion; whirl rapidly for about a minute. This will equalize the coat or film of bitumen and get rid of superfluous solution. When taken from the whirler the plate will be ready at once for the printing frame. These plates do not deteriorate, and a stock of them may be prepared and stored away in the dark till wanted. Great care must be taken not to allow the slightest ray of daylight to fall upon them, else the action once set up, will continue, and spoil the plate. {50}

On examining the zinc plate after removing it from the whirler, it will be difficult to realize that there is really a sufficient film of bitumen on the zinc, but there will be quite sufficient.

In printing upon bitumen from negatives that have been varnished, it will be as well to rub the varnished surface of the negative with a pledget of cotton dipped in dry French chalk.

The same care in putting into the printing frame, as enjoined in the chapter on zinc printing with bichromated albumen, is requisite with these plates, as is also the applying the pressure by means of the screws. The exposure to light will vary from ten minutes in the sun, to two or three hours in the shade.

The immersion in the acid water will have removed the shiny appearance of the zinc, and the matt surface will enable the operator to see if all the requisite details of the image are visible. If not, and they are covered with bitumen, another immersion in the turpentine will complete the development; but if any of the lines are rotten or the details are dissolved away, the exposure has been too short, and the plate will require repolishing and another exposure.

The image being satisfactory, the water is blotted off with clean blotting paper and allowed to dry. Don’t use heat for drying. It may then be exposed to light for a few minutes. This is not absolutely necessary, although it tends to make the image finer. The plate is now ready for etching in relief.

We have now treated of the various stages necessary to obtain a photographic transfer upon zinc, from a drawing or engraving, in line, in dot, or in stipple, first by making therefrom, in the camera, a negative—same size, reduced, or enlarged—and from that negative a print on zinc, either in ink on an albumen basis, or in bitumen.

These transfers can be used, either for yielding re-transfers for lithographic press, or (as is at present our intention) for etching into relief, for use as blocks for printing from letter-press.

Before proceeding to instruction for etching these photographic transfers into relief, we will consider the method of dealing with the direct transfer of drawings, in line or chalk, to zinc, without the intervention of photography.

For direct transfers to zinc, the picture is drawn by the artist the exact dimensions of the finished block; if in line, on ordinary lithographic writing transfer paper, in ordinary lithographic writing ink, just in the same way that an ordinary line subject is treated for ordinary lithography.

If the subject is in chalk, it may be drawn on a grained lithographic stone, which is rolled up, etched, washed out, again rolled up, then the transfer is pulled; or the picture may be drawn upon specially prepared transfer paper, like Josz’s polygraphic transfer paper, or other grained paper made for the purpose; or the subject may already be on stone, as a lithograph, or it may be a copper-plate engraving, in which case transfers are pulled and then put down upon zinc in the ordinary way.

In making drawings on lithographic transfer paper, great care must be taken to avoid touching the surface with the fingers, as finger-marks will transfer and roll up black. In line work all lines must be firm and black; no attempt must be made to get effect by using thin or pale ink.

In chalk work, also, the drawing must be firm and strong, and the corrections and alterations made on the transfer, not left to be done on the stone. If the corrections or alterations are small, they may be removed with an ink eraser, or by careful washing with turpentine, so that all the chalk is removed; if the {52} correction be large, paste a piece of clean transfer paper over the place, spreading the paste as thin as possible; gum must not be used.

The drawing on transfer paper being obtained, the next step is to transfer it to stone; then, after rolling up and proving, another transfer is made, which is to zinc.

From an engraved copper plate a transfer is made on India or upon Scotch transfer paper, on either a copper-plate press or a lithographic press, and then transferred direct to the zinc.

The engraved copper plate is first of all examined to see that all the old ink is out of the lines; if not, wash with turpentine and wipe quite dry; then, in a piece of clean linen rag, tie up some plate re-transfer ink; warm the copper plate, either on the hot plate or over a Bunsen burner, until it can be barely held in the hand; then, holding it in a piece of cloth to protect the fingers, rub in the ink tied up in the linen rag, until sufficient is melted to well cover the surface, taking care to see that the ink is rubbed well into the lines. Then take a piece of clean, soft rag and wipe off the ink from the surface of the plate carefully, so as not to remove it from the reversed lines; this is best secured by wiping across the lines, not with them. When the surface of the plate is quite free from ink, rub the lower part of the palm of the hand upon a ball of whiting, and proceed to polish the surface of the plate. Do not get too much whiting upon the hand, else it may stick to the ink and prevent it adhering to the transfer paper.

Now place a piece of clean transfer paper (India or Scotch), a little larger than the plate, face downward upon a piece of clean paper, sponge the back with a damp sponge, then let it lie a few minutes, so as to get evenly damp all through.

Now see that the press is ready. If a copper-plate press is to be used, see that the bed is free from grit, and that the blankets are in place; if a lithographic press is to be used, put in a stone, wipe it free from grit, and see that the scraper is all right; remove the tympan if of leather, but if of zinc or millboard it is all right. Now put the inked and polished copper plate upon the stone, and the damp transfer paper, face down, upon the copper plate; then upon the transfer paper place a piece of printer’s blanket, turn down the tympan, or put a piece of thin millboard over the blanket, run the bed of the press under the scraper, turn down the lever, and, if necessary, adjust the pressure (a good nip is necessary), then run the bed through; now raise the lever, pull out the bed, lift the tympan and blanket, reverse the plate, and pull {53} through again. Now gently warm the plate, and carefully lift away the transfer paper, which should contain the picture with every line firm and sharp; if it is not so, sufficient pressure has not been used, or the transfer paper has been made too damp, or sufficient ink has not been put into the lines.

The transfer, either drawn in line or in chalk, or from a plate, being obtained, it is next transferred to a polished litho stone. Of course, the picture can be at once transferred to the zinc which it is intended to etch, but it will be found best to first of all transfer to stone, then from the stone pull a transfer, and transfer that to the zinc, so that in case of an accident during the etching another plate can be quickly prepared. Before placing them upon the stone, the prepared transfers should lie in a damping book until evenly damp.

Now take a polished litho stone and place it in front of a fire or in the sun until it is quite dry, then place it upon the bed of the press, and adjust the pressure; then place the transfer upon the stone in such a manner that it lies without any slurring. Next place a piece of clean paper upon the transfer, then the blanket, lower the tympan, run in the carriage, lower the lever, and pull through; then lift the lever, draw back the carriage, turn the stone round and pull through again, then sponge the back of the transfer with water and pull through again, repeating the damping, and pulling through three or four times. Now with a wet sponge saturate the back of the transfer with water, and lift away the paper, then wash away the composition, leaving the image on the stone; now cover it with thick gum solution, and allow it to dry.

If more than one transfer is in hand at a time, they are trimmed as closely as possible and pasted with very thin paste close together upon a large piece of paper, and then all can be transferred at one operation.

The gum upon the stone being dry, wash it off carefully with clean water, then roll up with transfer ink. Clean away any dirt there may be with sponge and snake stone; where the snake stone cannot be used, a piece of pointed wood, dipped into acid gum, will clear way the dirt. Take care to have the wet sponge handy so as to prevent the acid spreading upon the work; now roll up as strong as possible, then etch, by passing over water acidulated with nitric acid of such a strength that it just slightly effervesces when the stone is touched; saturate a sponge with the weak acidulated water and go gently over the stone, then with another sponge charged with clean water, wash off the acid. Now again roll up with transfer ink as strong as possible, and pull the transfer. Chalk drawings are transferred to stone in the same way, then etched, but the acid water is allowed to act a little longer than for a line transfer, and after {54} washing away the etching solution, the picture is washed out with clean turpentine, then wiped with a sponge, gummed in, fanned dry, moistened with a wet sponge, and the water removed. Then the image is rolled up with transfer ink, and the transfers pulled for subsequent etching.

To transfer to zinc, take a piece of polished zinc and immerse it in the graining bath (page 40) for about a minute; then remove it, wash it under the tap, and rub it with soft sponge; then wipe it dry with a soft rag, and warm the plate slightly; lay it upon a litho stone in the press, lay the transfer (which has been lying in the damping book) upon the zinc plate; lay upon the transfer the piece of blanket, lower the tympan and pull through; then damp the back of the transfer, pull it through again; then reverse the plate, dampen the back of the transfer, pull through again; again dampen the back of the transfer, and again pull through; now saturate the transfer with water, peel off the paper, remove the composition, and apply with a sponge a sufficiency of a solution of gum (thickness of cream), 5 ounces; decoction of nutgalls, 10 ounces. The decoction of nutgalls is made as directed on page 56.

Allow this to stay on the zinc for about a minute, then wash off, cover with plain gum, fan dry, and dip a sponge in gum and rub over the plate; now dip a soft rag into the gum, then into the etching ink (page 57) mixed with a little cocoanut oil or mutton fat and middle varnish, continuing the application of gum and ink until the whole of the picture is sharp, black, and strong. Be sure and keep the plate well covered with gum and the ink as thick as possible.

The plate is now dusted with finely powdered resin, sponged with a wet sponge, and then is placed in the etching trough containing water and just sufficient nitric acid to taste; in this the plate remains about half a minute, rocking the etching trough gently all the time; now remove the plate, wash it under the tap, rubbing gently back and front with a sponge, then dry by gentle heat; next coat the back, edges, and margin and portions of the front which are too large to etch away, with thin shellac varnish. When dry proceed to etch as directed in the next chapter.

Instead of inking up with the rag after etching with the acid gum, wash off, then roll up with a leather roller charged with the etching ink mixed with a little cocoanut oil, and used as stiff as it is possible to work it, until the image has taken in all possible, damping the zinc with a sponge directly it shows any signs of getting dry; then dampen slightly, and repeat as above. Next immerse it in the etching bath as before; wash well, and dry; coat the back, edges and margin on the front with shellac varnish, when the plate will be ready for etching.

For etching transfers on zinc, whether photographic or direct, we shall require the following apparatus: A slab of iron about 24 × 18 inches and ¹?/?₂ or 1 inch thick, supported horizontally upon four legs, and heated by an atmospheric burner, arranged somewhat like a gridiron so that the heat is even all over. A set of rollers on litho stock, one of leather, one of flannel, and one or two glazed rollers, the same as lithographers use for tint printing—we also require an etching box—i. e., a wooden tray, 30 × 24 inches, and 8 inches deep, well made of seasoned wood, lined with either pitch (with a little tallow added), or gutta-percha, and mounted upon rockers.

This box will require a firm table for its support during the etching, said table standing as close as convenient to a sink and water tap.

The other requisites used during etching, are, nitric acid, turpentine, gum Arabic of a good quality, some powdered nutgalls, three or four sponges, some finely powdered resin, a flat camel’s-hair brush, a solution of shellac in spirits of wine, and the following inks:

First the etching ink, composed of beeswax one-quarter ounce, Russian tallow two ounces, bitumen half an ounce, middle varnish two ounces.

Melt these together in a pan over a fire, or Bunsen burner, stirring well during the operation, so as to mix them thoroughly; when all are melted, add five ounces of ordinary letterpress printing-ink, and thoroughly mix; then allow to boil and continue the heat until the gas escaping from the bursting bubbles explodes upon the application of a lighted taper; then remove all from the fire, and allow to cool.

For a hard ink, for use after the plate is etched deep enough, and the resist is cleaned off, mix

Melt, then cool and mix with turpentine to make it the consistency of soft soap.

Now, with these and a solution of gum Arabic (in cold water), the thickness of cream, add one-quarter pint of a decoction of nutgalls to each quart of gum solution. The decoction of nutgalls is made by adding one-quarter pound of bruised nutgalls to one and one-half pints of water, in an earthenware vessel (not metal); boil, then allow to stand at the fire and simmer gently for six hours, keeping the vessel covered over; then allow to cool, filter and add the proper quantity to the above gum solution.

We will assume that a suitable place is provided for carrying on the operations to be described, in the shape of plenty of bench room, and a good light to work by.

The first stage in etching a zinc plate in relief is, to slightly warm it upon the hot plate, then allow it to cool (by-the-bye, it will be very convenient to have a clean litho stone handy for placing the plate upon to cool quickly). The plate being cold, with a piece of soft sponge carefully smear it over with the gum solution, allow the gum to dry, spontaneously, in a cold current of air; if heat be applied the gum will crack and bring away the image from the plate.

Whilst the gum is drying, with a palette knife place equal parts of transfer ink (page 44) and of etching ink (page 54) upon one corner of the inking slab, then thin to the consistency of cream, with middle varnish, thoroughly incorporating the three ingredients with the palette knife.

Now place a little of this ink upon the leather roller and roll vigorously upon the slab, so as to distribute the ink thoroughly upon both roller and slab; be careful not to get too much ink on the roller, nor to have it too thin; in fact, work the ink as stiff as is possible.

Now lay the zinc upon a piece of clean paper, and sponge it gently over with a wet sponge, so as to loosen the film of gum, then squeeze the sponge nearly dry, and pass it over the plate again, so as to insure it being evenly damp all over, but be careful not to make it too dry.

Now proceed to roll up, by passing the charged roller to and fro over the plate, using moderate pressure and slow motion, recharging the roller at short intervals from the inking slab. Occasionally use the damp sponge so as to keep the plate sufficiently damp to resist the ink.

If the roller slides instead of rolling, wipe it with an old linen rag, which will remove the moisture; then recharge the roller again upon the slab. {57}

The rolling is continued until the whole image is an intense black, when it is carefully dusted over with very finely powdered resin applied with a broad camel’s-hair brush, taking care that all the image gets covered. Then rub it gently with a wet, soft sponge and place it in the etching box containing a mixture of water and nitric acid, the acid being only just perceptible to the taste.

The plate should remain in this for one minute (the box being kept rocking); it is then removed, and thoroughly washed back and front under the tap. Rub it gently with a clean soft sponge.

This etching is merely to remove any traces of gum or dirt from the zinc which would interfere with the shellac varnish holding.

Now dry the plates, using gentle heat, then coat the back with thin shellac varnish to protect it from the acid; do the same to the margin of the picture on front, also varnish the centre of any very broad whites up to half an inch of the image, so that the acid dissolves no more zinc than is necessary. Now examine the image carefully, and if any of the lines are defective touch them up, and make any alterations and additions required.

The plate is now ready for the first etching, for which purpose a little nitric acid is added to the water in the etching tray—precise directions cannot be given as to how much acid to add, as so much depends upon the area of zinc on the plate that requires dissolving; practice, however, will soon enable the operator to judge the proper quantity. If too much acid is added, the plate will quickly be covered with myriads of minute bubbles, in which case it must be instantly removed, well washed, and the bath diluted with water before the plate is reimmersed. If, on the other hand, there is too little acid present, the action is too slow, and more must be added.

The first etching must be carefully watched, and the rocking continued, until the application of the finger-nail to the margin shows that the zinc inside has been dissolved away to a depth of about the thickness of a visiting card.

The first etching is the most important of the whole, as unless a sufficient depth be attained the sharp lines will not be obtained; and as the ink is not yet capable of resisting too strong acid, great care must be taken that the work is not damaged; proceed cautiously, adding acid from time to time as required.

As a rule, the first etching will take from five to ten minutes (the tray being kept rocking all the time).

When it is judged that the first etching has been carried far enough, remove the plate from the tray, wash it well under the tap, rubbing gently with a {58} sponge, so as to remove the scum left by the acid, dry by means of gentle heat, then allow it to cool.

When the plate is quite cold, smear it over with gum solution, and with a piece of cardboard, fan the gum dry.

Now sprinkle the inking slab with turpentine, and with a cloth wipe the slab clean. Take a piece of etching ink and thin it with middle varnish, mixing them well with the palette knife upon the slab; now take the leather roller, and with the palette knife place a little of the ink upon it, and roll up on the slab until both roller and slab are well coated; but on no account must there be too much ink, nor must it be too thin.

Now lay the zinc down on the bench, on a piece of clean paper, and with the wet sponge carefully wash off the gum; then wipe all superfluous water off the plate, and roll up with the leather roller charged as above; roll the plate first one way, and then the other, keeping the zinc evenly damp all over, else the ink will catch in the whites, and probably spoil the picture. When the rolling is completed, and as much ink as possible has been piled on, the zinc will be nearly dry. If not, allow it to stand in a cold current for a little time, then take it to the drawer in which the powdered resin is kept, and smear the plate all over with the powder. Now brush as much of the resin away as will come, using the brush from all sides, so that all the lines get evenly coated, not only on the top, but upon the sides; this being done, take a damp sponge and carefully remove the superfluous resin from the whites, or unprotected zinc.

The plate is now ready for the second etching, and the solution in the etching tray must be reinforced by the addition of a little acid; but do not add too much at once. It will be far best to add a little at a time, and then, as soon as the zinc shows there is no action going on, add a little more; an easy and simple method of ascertaining whether any acid be present or not is to wipe the bare metal with the tip of the finger, and if that spot (which will be brighter than the surrounding parts) does not speedily resume its dingy color, the acid is exhausted.

The plate being immersed in the solution, set the tray rocking, and pay attention to the remarks above. At the end of ten minutes remove the plate from the tray, wash it under the tap, rub it gently with soft sponge, then remove as much of the water as possible, and examine the progress made by the acid. This can be seen by the lines being bare below the ink, in which case the etching has been carried far enough, and if not stopped, there would be danger {59} of under-cutting; if, however, no progress has been made, add a little more acid to the solution, replace the zinc, and rock again for another five or ten minutes.

The second etching being effected, the zinc is carefully washed, and the scum left by the acid is carefully sponged away; now stand the zinc up near the hot plate, so that it will get the benefit of a gentle heat, and when quite dry lay it upon the hot plate (which should be heated to a temperature of 120° to 150°F.) face up, with a piece of brown paper between the zinc plate and the hot plate.

As soon as the zinc plate begins to get hot, there will be a tendency to curl slightly away from the hot plate, which, if allowed, would prevent the ink being evenly melted. To prevent this, take a brad-awl in each hand, and press down the sides of the zinc, taking care not to touch any of the picture.

Allow the zinc to remain on the hot plate until the ink and resin are melted and run down to the bottom of the etching, then remove it and lay it on the cold slab until the plate is cold.

When cold, smear the plate with the gum solution, fan it dry (never use heat for drying the gum), moisten with wet sponge, roll up again (use the leather roller), using the ink pretty stiff on the inking slab; keep the surface of the zinc well moistened. When the roller gets too much water upon it, pass a piece of damp cheese-cloth over it to remove the water; then roll the roller vigorously on the slab until it again bites the ink. Continue rolling the zinc until all portions have received due attention from the roller. N. B.—Some of the closest work will be quite blocked up this time, and each subsequent rolling will block up more and more, until only the very open work will be left.

Now allow the zinc to get dry, then cover it with resin, brushing from all sides, so as to coat the sides of the lines as well as the top, and then remove all superfluous resin from the whites with a damp sponge. The zinc is now ready for the next etching, for which more acid is added to the solution in the etching tray.

Rock the tray carefully, watching the zinc to see that the acid is neither too weak nor too strong, until the progress can be seen by examining the plate; the time, with the proper quantity of acid, is twenty to thirty minutes.

When the etching has proceeded far enough, after washing and sponging, again allow it to dry, then place it upon the hot plate until the ink is melted and runs down the sides of the lines; then cool, smear with gum, fan dry, moisten with sponge, and roll up as before; dry, cover with resin, using a {60} camel’s-hair brush, then dampen with a sponge and give a fourth etching, using the same precautions as to strength of acid and duration of rocking as before.

Now cool the plate; get a little more ink on the roller, and roll the plate whilst cold. When the surface of the lines has a nice even coat of ink upon each and all (coarse and fine), again warm the zinc on the hot plate until it is just too hot to hold in the fingers; then cool it again, varnish the back with shellac varnish, then make a mark with a blunt point, in the ink on the margin, so as to lay a short line of zinc bare to the action of the acid.

The round of operations is repeated; but for rolling up for the fifth and subsequent etching, a flannel roller is used, and more ink will be required upon the slab; it will also require to be a little thinner.

For some subjects six or seven etchings will be required, whilst for others—especially where there are whites that are too small for cutting out with a fret saw or router—ten or twelve etches will be required. Practice, the best teacher, will soon enable the operator to judge how many are required.

The etching having been carried as deep as is judged sufficient, sprinkle the plate liberally with turpentine, and with a stiff scrubbing brush loosen the ink from the lines, and wash it off with a solution of American potash.

The plate being cleared from all ink, etc., is now examined carefully. The sides of the lines will show each etching, by a series of irregular steps. If the plate be put into the press in this condition, the chances are that before many copies had been made, these steps would take more or less ink from the rollers, and blur the image; therefore, before passing it into the hands of the printer, the plate will require etching two or three times more, to get rid of these irregularities.

This is done by warming the zinc on the hot plate, and then, whilst still warm, rolling up with a fine glazed roller charged with the hard etching ink from a clean inking slab.

Roll the zinc firmly, first one way and then the other, so that all the tops of the lines get well coated with ink; now make a mark on the margin with a blunt point in the ink, so as to lay a short line of zinc bare to the action of the acid.

Next empty the etching tray, put into it some clean water, and add sufficient acid to make it taste like strong vinegar; in this immerse the plate, and keep rocking for ten or fifteen minutes, or until the mark on the margin, when felt with the finger-nail, shows that it has attained a depth about the same as that obtained in the first etching. {61}

Now wash the plate under the tap, and wash off the ink with turpentine, followed by a solution of American potash; again wash and dry on the hot plate. Now examine, and if the lines are free from the steps, the plate is finished, but if not, the operation must be repeated until the steps are all removed.

Be careful to cover the surface of the block thoroughly with the ink, else the acid will spoil the picture.

The plate is now ready either for mounting for the press, or for electrotypes being taken from it; if the former, the deep whites are cut away with the router or fret saw, the edges are trimmed or bevelled, holes are drilled and counter-sunk at convenient places, for the insertion of nails or screws to fix the zinc to the wooden block, to make the surface type high.

The object aimed at in the instruction in Part I. is the production of relief blocks on zinc from an original in black and white, which original may be a drawing made purposely for reproduction, or it may be from a drawing already in existence, a woodcut, or engraving, the picture being rendered entirely in line, or a chalk drawing may be used. In fact, any subject that is capable of being worked from either at a type press or by ordinary (monochrome) lithography. Washed drawings, or oil or water color drawings are not applicable.

In fixing plans, or drawings on the easel, prior to photographing them, if they are cockled, and difficult to get flat, pins may be placed anywhere, so long as the lines are not interfered with, for these pins may be painted out with a camel’s-hair brush and gamboge or Indian ink. It is important that the plans or drawings be as flat as possible, as if the lines are cockled, they will not be photographed straight.

In photographing drawings on tracing paper or cloth, a piece of white paper should be placed behind them.

When, from an original of black lines on a white ground, it is desired to make a reverse block—i. e., white lines on a black ground—a negative is first made from the original, and from that negative a transparency is made; and a print made upon the zinc from that transparency will be a reverse of the original.

Thus far I have tried to make plain the details of a process which is as fascinating and as pretty as any in photography, and which supplies results which could not be attained by the most expert workers two years ago. And since those experts first obtained even tolerable results by zinc etching, like {62} everything else in photography, it has made wonderful progress. At first we were delighted and content when a block was obtained with relief sufficient to enable us to print it upon an ordinary press with type. But now we can get from the zinc surface all the qualities which are given by the lithographic stone. Indeed, the process of zincography bears a very strong general resemblance to that of lithography; of course, it varies therefrom in matters of process detail. The manipulations of zincography, however, are no more complicated in their nature than the details of printing, etc., from stone. Crayon drawings, ink work in line and stipple, rubber work, in fact, anything that can be drawn on stone can be drawn on properly prepared zinc, with the exception of engraved lines (intaglio), the structure of the zinc not giving the yielding brittleness of stone. The great departure made possible by zinc plates exists in the fact that they can be bent to the surface of a cylinder, thus displacing the reciprocating bed and stop-cylinder of the lithographic press with the continuously rotating plate and impression cylinder of the zincographic press, which, at the same driving speed, produces double the number of impressions printed on the lithographic press. To Mr. Bernard Huber, of the Huber Printing Press Company of Taunton, Mass., belongs the credit of designing the only American zincographic press in existence, and which is now in successful operation in several lithographic establishments. It is a thoroughly American machine in design and construction, and while no glowing prophecies of its immediately taking the place of lithographic presses are indulged in, yet this kind of press has its place and use, and will by its qualities win favor in the trade.

Many lithographers are beginning to give correct attention to zincography, but few are willing to give the time and constant experimenting to the subject that has been given by Messrs. Harris & Jones, who during the past three years have operated the zincographic presses in their lithographic establishment known as the Providence Lithograph Co. Having taken the selling agency of the Huber zincographic press, they offer to those who buy the press full instructions in zincographic surface printing.

These suggestions are given right here, first because we are now about to take a step higher in zinc etching—a step which will lead us to results which lithography can scarcely equal in some particulars—and second, because it is the policy of this work to withhold no information which the novice will need in supplying himself with a perfect outfit for doing the best of work. For the same reason the advertisers have been chosen, rather than received in the usual way.