As colour, according to the regular scale descending from white, ceases properly with the last of the tertiaries, olive, in theory the neutral black would here form a fitting conclusion. Practically, however, every coloured pigment, of every class or tribe, combines with black as it exists in pigments—not simply being deepened or lowered in tone thereby, but likewise defiled in colour, or changed in class. Hence there arises a new series or scale of coloured compounds, having black for their basis, which, though they differ not theoretically from the preceding order inverted, are yet in practice imperfect or impure. These broken compounds of black, or coloured blacks and greys, we have distinguished by the term, semi-neutral, and divided them into three classes: Brown, Marrone, and Gray. What tints are with respect to white, they are with regard to black, being, so to speak, black tints or shades.
The first of the series is Brown, a term which, in its widest acceptation, has been used to include vulgarly every kind of dark broken colour, and is, in a more limited sense, the rather indefinite name of a very extensive class of colours of warm or tawny hues. Accordingly there are browns of every denomination except blue; to wit, yellow-brown, red-brown, orange-brown, purple-brown, citrine-brown, russet-brown, &c. But there is no such thing as a blue-brown, nor, strictly, any other coloured brown in which blue predominates; such predominance of a cold colour at once carrying the compound into the class of gray, ashen, or slate. Brown comprises the hues called dun, hazel, auburn, feuillemort, mort d'ore, &c.; several of which have been already mentioned as allied to the tertiary colours.
The term brown, then, denotes rightly a warm broken colour, of which yellow is a chief constituent: hence brown is in some measure to shade what yellow is to light. Hence, also, proper quantities of either the three primaries, the three secondaries, or the three tertiaries, produce variously a brown mixture. Browns contribute to coolness and clearness by contrast when opposed to pure colours, and Rubens more especially appears to have employed them upon this principle; although the same may be said of Titian, Correggio, Paulo Veronese, and all the best colourists. Being a sort of intermedia between positive colours and neutrality, browns equally contrast colour and shade. This accounts for their vast importance in painting, and the necessity of preserving them distinct from other colours, to which they give foulness in mixture; and to this is due their use in backgrounds and in relieving of coloured objects.
The tendency in the compounds of colours to run into brownness and warmth is one of the common natural properties of colours which occasions them to deteriorate or defile each other in mixture. Brown by consequence is synonymous with foul or dirty, as opposed to fair or clean; and hence brown, which is the nearest of the semi-neutrals in relation to light, is to be avoided in mixture with light colours. Yet is it an example of the wisdom of nature's Author that brown is rendered, like green, a prevailing hue, and in particular an earth colour, as a contrast which is harmonized by the blueness and coldness of the sky.
This tendency will likewise explain the use of brown in harmonizing and toning, as well as the great number of natural and artificial pigments and colours so called. It was the fertility and abundance of browns that caused our great landscape-colourist Wilson, when a friend went exultingly to tell him that he had discovered a new brown, to check him in his characteristic way, with—"I'm sorry for it: we have gotten too many of them already." Nevertheless, fine transparent browns are obviously very valuable.If red or blue in excess be added to brown, it falls into the other semi-neutral classes, marrone or gray. The wide acceptation of the term brown has occasioned much confusion in the naming of colours, since broken colours in which red, &c. predominate, have been improperly called brown. That term, therefore, should be confined to the semi-neutral colours, compounded of, or like in hue to, either the primary yellow, the secondary orange, or the tertiary citrine, with a black. The general contrast or harmonizing colour of such compounds will consequently be more or less purple or blue.
The number of browns is great, as may be seen by the following list. This list, however, is good, and includes a considerable proportion of permanent pigments.
241. ASPHALTUM,
Asphalt, Bitumen, Mineral Pitch, Jew's Pitch, Antwerp Brown, Liquid Asphaltum, &c., is a sort of mineral pitch or tar which, rising liquid to the surface of the Lacus Asphaltites or Asphaltic Lake (the Dead Sea) concretes there by the natural action of the atmosphere and sun, and, floating in masses to the shores, is gathered by the Arabs. The French give it an additional name from the region of the lake, to wit, Bitumen of Judea; and with the English, from the same cause, it has the alias of Jew's pitch. Asphaltum is not so called, however, after the lake, as is asserted by a writer in the EncyclopÆdia: it is just the reverse—Pliny says, "The Asphaltic lake produces nothing but bitumen (in Greek, asphaltos); and hence its name."
A substance resembling asphalt is found at NeufchÂtel in Switzerland, and in other parts of Europe. A specimen of the native bitumen, brought from Persia, and of which the author made trial, had a powerful scent of garlic when rubbed. In the fire it softened without flowing, and burnt with a lambent flame; did not dissolve by heat in turpentine, but ground easily as a pigment in pale drying oil, affording a fine deep transparent brown colour, resembling that of commercial asphaltum; dried firmly almost as soon as the drying-oil alone, and worked admirably both in water and oil. Asphaltum may be used as a permanent brown in water, for which purpose the native is superior to the artificial. The former, however, is now seldom to be met with, the varieties employed on the palette being the residua of various resinous and bituminous matters, distilled for the sake of their essential oils. These residua are all black and glossy like common pitch, which differs from them only in having been less acted upon by fire, and thence in being softer. At present asphaltum is prepared in excessive abundance as a product of the distillation of coal at the gas manufactories, and is chiefly confined to oil-painting, being first dissolved in turpentine, which fits it for glazing and shading. Its fine brown colour and perfect transparency are lures to its free use with many artists, notwithstanding the certain destruction that awaits the work on which it is much employed, owing to its tendency to contract and crack by changes of temperature and the atmosphere; but for which, and a slight liability to blacken, it would be a most beautiful, durable, and eligible pigment. The solution of asphaltum in turpentine, united with drying oil by heat, or the bitumen torrefied and ground in linseed or drying-oil, acquires a firmer texture, but becomes less transparent and dries with difficulty. If common asphaltum, as usually prepared with turpentine, be used with some addition of Vandyke brown, umber, or Cappah brown ground in drying oil, it will gain body and solidity which will render it much less disposed to crack. Nevertheless, asphaltum is to be regarded in practice rather as a dark varnish than as a solid pigment, and all the faults of a bad varnish are to be guarded against in employing it.
It is common to call the solution in turpentine Asphaltum, and the mixture with drying-oil Bitumen: the latter is likewise known as Antwerp Brown. A preparation for the use of water-colour artists is employed under the name of Liquid Asphaltum.
242. BISTRE
is extracted by watery solution from the soot of wood fires, whence it derives a strong pyroligneous scent. It is a very powerful citrine-brown, washes well, and has a clearness suited to architectural subjects. Its use is confined to water-colour painting, in which it was much employed by the old masters for tinting drawings and shading sketches, before the general application of Indian ink to such purposes. Of a wax-like texture, it is perfectly durable, but unfitted for oil, drying therein with the greatest difficulty.
A substance of this kind collects at the back of fire-places in cottages where peat is the constant fuel burnt; which, purified by solution and evaporation, yields a fine bistre, similar to the Scotch. All kinds of bistre attract moisture from the atmosphere.
243. BONE BROWN
and Ivory Brown are obtained by roasting bone and ivory until by partial charring they become of a brown colour throughout. Though much esteemed by some artists, they are not quite eligible pigments, being bad driers in oil, the only vehicle in which they are now used. Moreover, their lighter shades are not permanent either in water or oil when exposed to the action of strong light, or mixed in tint with white lead. The palest of these colours are the most opaque: the deepest are more durable, and most so when approaching black. Neither bone nor ivory brown is often employed, but the former may be occasionally applied in forming clear, silvery, warm grays, in combination with zinc white.
244. BURNT UMBER
is what its name denotes, and has a deeper shade with a more russet hue than the raw umber. A quiet brown, it affords clear and warm shadows, but is apt to look rather turbid if used in great depth. It washes and works capitally in water, and dries quickly in oil, in which it is employed as a siccative. Perfectly stable in either vehicle, it may sometimes be substituted for Vandyke brown, is eligible in fresco, and invaluable in buildings. Where the lakes of madder require saddening, the addition of burnt umber increases their powers, and improves their drying in oil. It contains manganese and iron, and may be produced artificially. The old Italians called it falsalo.
245. CALEDONIAN BROWN
is a permanent native pigment, the use of which is confined to oil. A magnificent orange-russet brown of considerable transparency, it is marked by great depth and richness, and will be found serviceable where a powerful brown of the burnt Sienna class is required.
246. CAPPAH BROWN,
or Cappagh Brown, is likewise a colour peculiar to oil. It is a species of bog-earth or peat, mixed with manganese in various proportions, and found on the estate of Lord Audley at Cappagh, near Cork. The specimens in which the peat earth most abounds are of light weight, friable texture, and dark colour; while those which contain more of the metal are heavy and paler.
As pigments, the peaty Cappah brown is the most transparent and rich in colour. A prompt drier in oil, its surface rivels during drying where it lies thick. The other and metallic sort is a more opaque, a lighter and warmer brown pigment, which dries rapidly and smoothly in a body or thick layer. The first may be regarded as a superior Vandyke brown, the second as a superior umber. The two extreme kinds should be distinguished as light and deep Cappah browns; the former excellent for dead colouring and grounds, the latter for glazing and graining. These pigments work well in oil and varnish; they do not, however, keep their place while drying in oil by fixing the oil, like the driers of lead, but run. Under the names of Euchrome and Mineral Brown, they have been introduced into commerce for civil and marine painting.
247. CASSEL EARTH,
Terre de Cassel, or, corruptly, Castle Earth, is specially an oil pigment, similar to burnt umber but of a more russet hue. It is an earth containing bitumen, a substance which, with pit-coal, lignite or brown coal, jet, petroleum or rock oil, naphtha, &c., is looked upon as a product of the decomposition of organic matter, beneath the surface of the earth, in situations where the conditions of contact with water, and almost total exclusion of atmospheric air, are fulfilled. Deposited at the bottom of seas, lakes, or rivers, and subsequently covered up by accumulations of clay and sand, the organic tissue undergoes a kind of fermentation by which the bodies in question are slowly produced. The true bitumens appear to have arisen from coal or lignite by the action of subterranean heat; and very closely resemble some of the products yielded by the destructive distillation of those bodies.
Rich as is the tone of colour of Cassel earth, it is apt to lose this in some measure on exposure to light. MÉrimÉe remembers to have seen a head, the brown hair of which had been painted partly with the earth alone, and partly with a mixture of the earth and white; yet the hair where the white was employed was darker than that painted solely with the brown, the white having fixed the colour. To compensate for its thus fading, it should be mixed with pigments that are permanent, such as umber and lamp black. Like all bituminous earths, it needs the strongest drying oil. By calcination, a greater degree of intensity may be imparted to the colour, and perhaps a little more solidity. In landscapes it is of much service for the most vigorous portions of foregrounds and the trunks of trees, as well as for painting cavernous rocks or deep recesses in architecture. Compounded with burnt lake and a little Prussian blue, it gives a black the most profound.
248. CHALON'S BROWN
is a water-colour pigment, transparent and inclining to red; deep, full, and very rich. On exposure to light it becomes less russet, but is otherwise strictly stable.
249. COLOGNE EARTH,
incorrectly called Cullen's Earth, is a native bituminous earth, containing less bitumen than Cassel earth, and therefore drying more quickly. Darker than that variety, it is less transparent, and covers better. In its general qualities it resembles Vandyke brown, except that in combination with white, it affords a range of cooler brown tints. Useful for the shadows of buildings, it does not wash so well as sepia, and is preferred occasionally on that account. By some it has been called durable, by others branded as fugacious. According to Bouvier, brown hair represented by this colour has been known to disappear in six months, all the brown vanishing, and nothing remaining but a few black lines of the sketch. As it is similar in composition to Cassel earth, the safest course would be to mix it with umber, and not to employ it alone. Calcined, it acquires a reddish hue.
250. INDELIBLE BROWN INK.
Although this cannot be classed as a pigment, yet, being very useful in water-colours, it may be proper to describe its qualities. The ink is a rich brown fluid, and, as its name imports, is indelibly fixed on the paper as soon as it is dry; thus allowing the artist to work or wash over it repeatedly, without its being disturbed. If diluted with water to its faintest tint, it still continues to retain its indelible properties undiminished. It is generally used with a reed pen, and employed chiefly in architectural details and outlines.
Various brown inks, principally solutions of bistre and sepia, were adopted in sketching by Claude, Rembrandt, and many of the old masters. In modern times, a beautiful transparent brown for water-colour artists, known as Liquid Prout's Brown, has been extensively employed. This contains less fixative than the indelible ink, and is the vehicle with which nearly all Samuel Prout's drawings were executed.
251. LEITCH'S BROWN
is a permanent pigment peculiar to water painting. A most beautiful olive brown, soft and rich, it is admirably adapted for autumnal foliage tints and the like, either alone or compounded with burnt Sienna or cadmium orange. Transparent and clear in its washes, this is a most serviceable colour in landscape generally.
252. MIXED BROWN
can be produced in endless variety, either by adding a warm colour to black, such as yellow, orange, or citrine, or else by combining the three primaries, secondaries, or tertiaries in suitable proportions. By consulting the lists given of permanent pigments belonging to those classes, and by referring to the chapter on Black, it will be seen that no difficulty exists in obtaining durable mixed browns when required. For example, there may be formed from the primaries, a compound of aureolin, rose madder, and ultramarine; or from the secondaries, a mixture of cadmium orange, viridian, and madder purple. Of course, as with other mixed tints, the brown hue can be furnished not only by direct compounding of the colours on the palette, but by laying one colour over the other on the paper or canvass, or by stippling.
253. MUMMY,
Mummy Brown, or Egyptian Brown, is a bituminous product mixed with animal remains, brought from the catacombs of Egypt, where liquid bitumen was employed three thousand years ago in embalming. By a slow chemical change, it has combined during so many ages with substances which give it, as a rule, a more solid and lasting texture than simple asphaltum. Generally resembling the latter in its other properties and uses as a pigment, mummy is often substituted for it, being less liable to crack or move on the canvass. It must be remembered, however, that mummy varies exceedingly both in its composition and qualities; and as from its very nature and origin nothing certain can be said of it, but little reliance should be placed on this brown. Mummy belongs to the class of pigments which are either good or bad, according as they turn out. On the whole, we agree with the American artist, who has been more than once quoted in these pages, that nothing is to be gained by smearing one's canvass with a part, perhaps, of the wife of Potiphar. With a preference for materials less frail and of a more sober character, we likewise hold with Bouvier, that it is not particularly prudent to employ without necessity these crumbled remains of dead bodies, which must contain ammonia and particles of fat in a concrete state and so be more or less apt to injure the colours with which they may be united. The use of mummy is now confined to oil, in which, says Mr. Carmichael, a mixture of mummy and bitumen will dry and never crack. If this be the case, the compound would be preferable to either separate.
254. PRUSSIAN BROWN
is an iron oxide, containing more or less alumina, and prepared by calcining an aluminous Prussian blue, or treating an aluminous ferrocyanide of peroxide of iron with an alkali. Possessing the nature and properties of burnt Sienna, it is transparent, permanent, and dries well in oil. Of an orange hue, it is neither so rich nor so powerful as that pigment, and is better employed as a glaze than in body.
255. SEPIA,
Liquid Sepia, Seppia, or Animal Æthiops, is named after the sepia or cuttle-fish, also called the ink-fish, from its affording a dark liquid, which was used as an ink and pigment by the ancients. All the species of cuttle-fish are provided with a dark-coloured fluid, sometimes quite black, which they emit to obscure the water, when it is wanted to favour their escape from danger, or, by concealing their approach, to enable them with greater facility to seize their prey. The liquid consists of a mass of extremely minute carbonaceous particles, intermixed with an animal gelatine or glue, and is capable of being so widely spread, than an ounce of it will suffice to darken several thousand ounces of water. From this liquid, brought chiefly from the Adriatic, but likewise obtainable from our own coasts, is derived the pigment sepia, as well as, partially, the Indian ink of the Chinese.
Sepia is a powerful dusky brown, of a fine texture, transparent, works admirably in water, combines cordially with other pigments, and is very permanent. It is much used as a water-colour, and for making drawings in the manner of bistre and Indian ink; but is not employed in oil, as it dries therein very reluctantly. Extremely clear in its pale tints, and perhaps the best washing colour known, sepia must be used with caution, or otherwise heaviness will be engendered in the shades, so strong is its colouring property. Mixed with indigo, or, preferably, Prussian blue and black, it is eligible for distant trees, for a general shadow tint in light backgrounds, and for the shade of white linen or white draperies. With madder red it forms a fine hue, somewhat resembling brown madder, and with crimson lake and indigo gives an artistically excellent black. Sometimes alone and sometimes in combination with lamp black, or madder red and Prussian blue saddened by the black, it will be found useful in dark foreground boats, rocks, near buoys, sea-weed, &c. Compounded with aureolin, sepia yields a series of beautiful and durable neutral greens for landscape; and mixed with Prussian blue, affords low olive greens, which may be deepened into very cool dark greens by the addition of black. For hills and mountains in mid-distance, sepia combined with cobalt and brown madder is of service; or, for the dark markings and divisions of stones in brooks and running streams, the same compound without the cobalt. Mixed with purple madder, it furnishes a fine tint for the stems and branches of trees; and with French blue and madder red gives a really good black. Compounds of sepia and yellow ochre, gamboge, raw Sienna, or cobalt and aureolin, are severally useful. A rich and strong brown is formed by the admixture of madder red, burnt Sienna, and sepia; a tint which may be modified by omitting the sepia or the Sienna, or reducing the proportions of either. For Dutch craft, this tint and its variations are of great value. A wash of sepia over green very agreeably subdues the force of the colour.
256. WARM SEPIA
is the natural sepia warmed by mixture with other browns of a red hue, and is intended for drawings where it would be difficult to keep the whole work of the same tint, unless the compound were made in the cake of colour.
257. ROMAN SEPIA
is a preparation similar to the preceding, but with a yellow instead of a red cast.
258. VANDYKE BROWN.
This pigment, hardly less celebrated than the great painter whose name it bears, is a species of peat or bog-earth of a fine, deep, semi-transparent brown colour. The pigment so much esteemed and used by Vandyke is said to have been brought from Cassel; an assertion which seems to be justified by a comparison of Cassel earth with the browns of his pictures. Gilpin in his Essays on Picturesque Beauty, remarks that "In the tribe of browns—in oil-painting, one of the finest earths is known, at the colour shops, by the name of Castle-earth, or Vandyke's brown." The Vandyke brown of the present day is a bituminous ochre, purified by grinding and washing over. Apt to vary in hue, it is durable both in water and oil, but, like all bituminous earths, dries tardily as a rule in the latter vehicle. Clear in its pale tints, deep and glowing in shadows, in water it has sometimes the bad property of working up: for this reason, where it is necessary to lay on a great body of it, the moist tube colour should be preferred to the cake. With madder red, the brown gives a fine tint, most useful as a warm shadow colour; and with Prussian blue, clear, very sober neutral greens for middle distances. In banks and roads, Vandyke brown is the general colour for dragging over the surface, to give roughness of texture: compounded with yellow ochre, it affords a good ground tint, and with purple madder a rich shadow colour. In sunrise and sunset clouds, a mixture of the brown with cobalt yields a cold neutral green, adapted for those clouds at the greatest distance from the sun. For foliage tints, aureolin, French blue, and Vandyke brown, will be found of service; or as a glaze over such tints, the yellow and the brown. With raw Sienna, brown madder, Payne's gray, gamboge, and Roman ochre, this brown is useful. In a water-colour winter scene, when the trees are denuded of foliage, the net work of the small branches at the tops of them may be prettily given with cobalt and Vandyke brown, used rather dry, and applied with a brush having its hairs spread out either by the fingers or by drawing them through a fine-tooth comb before working. Grass is likewise represented readily by this means, and so are small trees on the summit of a cliff or in like positions.
The Campania Brown of the old Italian painters was a similar earth.
259. VERONA BROWN,
a pigment peculiar to oil painting, is a native ferruginous earth. A citrine brown of great service in tender drab greens, it forms with terre verte and the madder lakes rich autumnal tints of much beauty and permanence.
260. YELLOW MADDER,
Cory's Yellow Madder, or Cory's Madder, is classed among the browns for the same reason that Italian Pink was ranked among the yellows. It was stated in the eighth chapter that no true madder yellow, brilliant and pure, exists as a pigment at the present day, and certainly this preparation can lay no claim to the title. Except in name, it is an orange-brown of the burnt Sienna hue, and might therefore with more reason have been called Orange Madder. It is a good and permanent colour, rich and transparent, at present used only in oil, we believe, and chiefly as a glaze.
261. Cadmium Brown.
By igniting the white carbonate of cadmium, among other methods, a cinnamon-brown oxide is obtainable, of a very clear and beautiful colour if the process be well conducted. It is, however, not eligible as a pigment, owing to the rapidity with which the oxide is acted upon by the air. In water, especially, we have found this brown so eagerly absorb carbonic acid from the atmosphere as to become in a few months once more a carbonate, and as purely white as before. The same result is observable when the powder is exposed: some shown at the International Exhibition of 1862, on a glass stand, had to be removed, its label marked 'Cadmium Brown' being at last found attached to a sample of cadmium white. In oil, the conversion takes place less readily, that vehicle having the property of protecting, to some extent, pigments from oxidation. It is curious that even in a book a water-rub of the brown slowly but surely changes to white.
262. Catechu Browns.
Catechu is an extract of the Khair tree or acacia catechu of Bombay, Bengal, and other parts of India. With the exception of such earthy matters as are communicated to it during the preparation, or are added purposely as adulterants, catechu is entirely soluble both in water and alcohol. An aqueous solution has a reddish-brown colour, and gives the following results:—protosalts of iron thrown down olive-brown and persalts greenish-brown precipitates; salts of tin and lead yield brownish-yellow and brick-coloured deposits respectively; while acetate of copper or bichromate of potash furnishes brown residues. To our knowledge, none of these have been introduced as pigments, but a brown prepared by Dr. Lyon Playfair some years back from the catechu bark has been described as exceedingly rich, transparent, and beautiful; and recommended for painting if not too thinly applied.
263. Chrome Browns
are produced by various methods of several hues, tints, and shades, both by wet and dry processes. We have obtained them by many methods, of different degrees of permanence. Some very intense in colour have stood well, while others paler and more delicate have gradually greened, but none possessed the strict stability of the green oxides. Presuming a paucity of browns, these preparations of chromium would be worth further attention; but, with the objection of being—for browns—somewhat expensive, they have the far more fatal objection of not being wanted.
264. Copper Brown,
varying in hue, is obtainable, in the form of prussiate, &c., but cannot be recommended, however made.
265. French Prussian-Brown.
According to Bouvier, a colour similar to that of bistre, and rivalling asphaltum in transparency, is produced by partially charring a moderately dark Prussian blue; neither one too intense, which gives a heavy and opaque brownish-red, nor one too aluminous and bright, which yields a feeble and yellowish tint. Yielding to a rapture we cannot wholly share, he describes its qualities in the warmest terms. In his opinion, it has the combined advantages of asphaltum, mummy, and raw Sienna, without their drawbacks. "I cannot," he says, "commend too highly the use of this charming bistre-tint: it is as beautiful and good in water as in oil, perfectly transparent, of a most harmonious tone, and dries better than any other colour suitable for glazing. Closely resembling asphaltum in tint as well as in transparency, this brown is preferable to it in every point of view." As the colour is very quickly and easily obtained, the artist can judge for himself of its proper value. M. Bouvier's process is, to place upon a clear fire a large iron spoon, into which, when red hot, some pieces of the Prussian blue are put about the size of a small nut: these soon begin to crackle, and throw off scales in proportion as they grow hot. The spoon is then removed, and allowed to cool: if suffered to remain too long on the fire, the right colour will not be produced. When the product is crushed small, some of it will be found blackish, and the rest of a yellowish brown: this is quite as it should be. Chemically, the result is a mixture of oxide of iron and partly undecomposed or carbonised prussiate.
266. Gambogiate of Iron.
Dr. Scoffern read a paper at the Meeting of the British Association of Science, in 1851, describing this combination as a rich brown, like asphaltum, but richer, as well as more durable in oil. It has not been, however, employed as a pigment, or at least is not at present.
267. Hypocastanum,
or Chestnut Brown, is a brown lake prepared from the horse-chestnut. This now obsolete pigment is transparent and rich in colour, warmer than brown pink, and very durable both in water and oil; in the latter of which it dries moderately well.
268. Iron Browns,
native or artificial, are well represented on the palette, but nothing would be easier than to increase their number. Of all metals, iron is the richest source of colour, capable of affording all colours with the exception of white. None of them, however, are so numerous as the browns, a description of which would fill this chapter. Suffice it to state they are obtainable of every hue, tint, and shade, and are generally permanent. They are made on a large scale and sold under various names for house-painting, &c.
269. Manganese Brown
is an oxide of manganese, which is quite durable both in water and oil, and dries admirably in the latter. A fine, deep, semi-opaque brown of good body, it is deficient in transparency, but might be useful for glazing or lowering the tone of white without tinging it, and as a local colour in draperies, &c.
270. Nickel Brown.
A very pleasing yellowish brown is obtainable from nickel, bright and clear in its pale washes, and of some richness in oil. Unless thoroughly washed, it has a tendency to greenness in time.
271. Ochre Browns.
The slight affinity of sulphur for yellow ochre, with its merely temporary effect thereon, was observed in the eighth chapter, where allusion was made to the action of sulphuretted hydrogen and sulphide of ammonium on the earth. Sulphur alone, and in the dry state, ignited with yellow or other native ochres converts them into browns, varying in hue, and of greater or less durability. Those browns, however, which we have made by this process, although standing well in a book, have not withstood exposure to light and air. They have all become pale, whitish, or of a drab cast, evidently through the oxidation of the sulphur, or rather the sulphide of iron formed during the calcination. Practically, therefore, ochres have an antipathy to sulphur, moist or dry, by itself or in combination; and are, so to speak, the disinfectants of the palette. Ever waging war against sulphurous vapours, the native earths serve to protect a picture from the damaging influence of impure air, whether they be used alone, or employed in admixture with such pigments as are injured thereby.
272. Purple Brown
is a refuse manufacture from Indian red washings. A dull, heavy, coarse colour, it belongs to the class of common pigments which are unexceptionable for decorative painting, but scarcely suited to the higher branches of art. As this work professes simply to treat of artistic pigments, that have been, are, or might be, more than a passing reference to those colours exclusively adopted by house-painters, &c., would be out of place.
273. Rubens' Brown,
still in use in the Netherlands under this appellation, is an earth of a lighter colour and more ochrous texture than the Vandyke brown of English commerce: it is also of a warmer or more tawny hue than the latter pigment. Beautiful and durable, it works well both in water and oil, and much resembles the brown employed by Teniers.
274. Uranium Brown.
Yellow, red, orange, green, have been previously noticed as being derived from uranium, and to this list of colours may now be added brown. A warm rich hue of the utmost intensity may be produced, which possesses considerable permanence, although not equal to that of uranium yellow.
275. Zinc Brown.
A yellow-brown, so yellow that it might fairly have been classed with the ochrous colours of that denomination, is made by combining zinc with another metal by the aid of heat. Experience tells us that it is, chemically, a thoroughly good and stable pigment. Safely to be used in admixture, it is a clear, bright colour, affording good greens by compounding with blue. Of no great power, and semi-opaque, this yellow-brown or brown-yellow is superior to some of the pigments at present used, but is probably too much like them in hue and other properties to be of any special value.
Besides the preceding, there are those browns of a citrine or russet cast which are elsewhere described, such as raw umber, madder brown, &c. Moreover, there are numberless other varieties, obtainable from most of the metals, from many organic substances, and from a combination of the two. Of all colours, a 'new' brown is the most easily discovered: success may not be met with in seeking a yellow, red, or blue, or an orange, green, or purple; but it is strange if in the course of one's experiments a brown does not turn up. No difficulty, therefore, would have been found in greatly extending the present list; but it was felt that no advantage could have accrued by further multiplying the notices of a colour, with which we are already furnished so abundantly by nature and art, and which is capable of being produced in such profusion by admixture.
With the exception of ivory and bone browns, and perhaps Cassel and Cologne earths, all the browns commonly employed may be considered more or less durable.
