The standard space between words in ordinary roman lower-case type is the 3-space. This thickness is commonly accepted as the average spacing required for legibility in a printed page to be held in the hand. It gives comfortable legibility in sizes of type from 8-point to 14-point. Smaller sizes may be spaced with an average slightly wider, like the en quad, while for large types to be read at close range the spacing may be less than the 3-space average.

Wide measures, as a rule, require relatively wide spacing. Narrow measures are preferably thin-spaced, whether the lines are leaded or solid.

An apparently equal spacing between all words in a line means that in some cases there must be a slight variation in the width of the actual spaces used. The size and shape of the letters at the ends of words will often affect the amount of white space, especially in the larger faces of type.

There are several combinations of word endings which call for spaces thinner or thicker than the average in the line in order to make all the spaces appear equal. These little variations can be made while changing the spaces to justify the line. They need not, for the most part, take any extra time, while the resulting evenness in the spacing of the page will be noticeable. Good spacing without spending unnecessary time is usually a matter of following a few simple rules.

When necessary to use thinner spaces to get a complete word or syllable in the line, put these thin spaces after a comma, or between word endings like ——ew——, ——ya——. Word endings like ——yA——, ——wv——, ——yu—— can be very thinly spaced if necessary.

On the other hand, if a little extra space is needed to fill the line, increase the spaces between words ending with tall letters,——dl——, ——fb——, etc.

Abbreviated words and initials with the period (Mrs. Rev. M.D. Ph.D. etc.) are places where thin spaces are properly used.

A thin space is required before colons, semicolons, question marks, and exclamation marks, when these are cast on thin bodies. These points should be followed by an extra-wide space. That is, if the line is spaced with a 3-space as the average, a semicolon should have a 5-space before it and an en quad after. If the line is thin-spaced, the spaces before and after the semicolon are reduced also. In some fonts of type these punctuation marks are cast on thick bodies which furnish a slight shoulder on each side of the face of the mark. In such cases the extra spaces may not be required in ordinary composition.

When a question mark or an exclamation mark finishes a sentence, it should be followed by a space equal to that used after periods in other parts of the same matter.

The em dash usually should have a little space on each side of it, especially if the line is spaced with 3-spaces or wider. If the line is thin-spaced, the dash also may be set close to the adjoining words. Whenever possible avoid putting the dash at the end of the line in paragraphs; try to keep it within the line.

A short line, consisting of a word or syllable of two or three letters only, should be avoided at the end of a paragraph, especially in a measure of ordinary width. In a very narrow measure it may not be avoided. Where the other lines of the page are fairly well filled this short line will make an objectionable break in the matter. If it cannot be taken back to the preceding line, a little wider spacing of these lines will allow an additional word or syllable to be brought over to lengthen the objectionable short line.

It is desirable to end a paragraph with an em quad, if this is practicable, rather than fill the last line flush. Do not leave an ordinary space after the period.

When justifying the last line of a paragraph or a headline in which quads are used, keep the justifying spaces next to the types. Do not put small pieces at the end of a quad line or scatter them between the large quads. They will be easier to distribute if placed after the period.

Hyphenated words in a widely spaced line should have a hair space on each side of a thin hyphen; but this may not be necessary if the hyphen is cast on a thick body, as it is in some fonts.

The dollar sign $ is set close to the whole numbers in printing amounts of money: $25. When specifying fractions of a dollar (in tabular columns only) put a space between the sign and the decimal: $.25. The symbols for English money are also placed close to the figures, thus £105s2d.

When justifying lines some compositors commence respacing at one end of the line and increase the spaces in order till the line is full, regardless of the length of the words or the word endings, repeating this line after line. The result is that one side of the matter is spaced wider than the other—a most inexcusable fault. If a few spaces wider than the average must be used in the line, put these between long words or words with tall letters; and vice versa, if thin spaces are necessary, put them between short words or words with small letters. Do not wide-space short words and leave long words in the same line with thin spaces. Do not, however, if it can be avoided, allow wide spaces to be repeated nearly under each other, to produce noticeable straggling white spaces or “rivers” up and down the page. Spacing of this sort is particularly objectionable for good printing.

An old-time rule required an em quad after a period before beginning another sentence in the line. This is the practice in many places now, but there is an objection to the unnecessary large white spot which it makes in the ordinary page of reading matter. As a distinction between sentences it seems too conspicuous except in matter that is wide-leaded and wide-spaced. The modern practice in good work is to reduce this space to the double 3-space or the en quad, or even to the 3-space in small pages.

Another unnecessarily large space in narrow measure of solid or single-leaded lines is an em quad after the period or Roman numeral in numbered paragraphs. Where the period is used an en quad following it is sufficient.

In good composition quotation marks should not be crowded close against the words which they enclose, unless the lines are close-spaced. Commas and apostrophes cast on very thin types usually need a little space between the quote-marks they form and the words they enclose, especially if they are next to tall letters. A large capital A or a sloping italic capital at the beginning may not need the separating space after the inverted commas, and a period or a comma between the last word and the final quote-mark will furnish the needed separation.

“Q uote-marks properly spaced.”

“T hese are not well spaced. ”

“‘ Quotes’ within ‘quotes’ are like this.”

In open-spaced matter there should be a thin space between an exclamation or question mark and the final quote-mark, thus:

“ Do you wish to become a good compositor ?”

Letter-spacing, or inter-spacing, is frequently employed in headings and in job and display composition. It is rarely a good practice in ordinary lower-case composition in paragraph form. In very narrow measures, where word length or word divisions do not come right to make the lines the desired length, the letter-spacing of a few words is sometimes resorted to in order to extend the words. This should be done with care to avoid making such words conspicuous in the general appearance of the page. It is better to letter-space the whole line a little rather than to put excess spacing in one unimportant word.

Black-letter, Old English, Priory Text, Cloister Black, and similar varieties should not be wide-spaced, nor should they ever be letter-spaced. The beauty of such letters, which are now used for their decorative rather than utilitarian qualities, depends upon the consistent, well-balanced relation between the white and black spaces of the composition. The compactness of the letter shapes makes words that are compact and unified. As there are relatively close spaces between the strokes of the letters, so there should be thin spaces between the words of the lines and between the lines. Wide spaces between words do not necessarily make them more legible. A comparison of the two groups of lines following will show one as easy to read as the other, while the close-spaced example is less confusing in its detail.