Letter-spacing is often misused. It is safe to say that lower-case type should practically _never_ be letter-spaced, for the individual letters were designed for close combination with other letters of the alphabet. If it becomes necessary to fill out a line it is preferable to put all the extra space between the words even though the resultant "holes" are distressing to the eye. Sometimes with very large types it is permissible to letter-space in a minor degree, as the spaces between the letters naturally are larger and letter-spacing does not detract too much from the appearance of the line, especially if it is distributed according to the irregular space between the different letters as normally set.
With capitals or upper-case letters the conditions are different. Then it is frequently a great advantage to use letter-spaces, even considerably; but this depends upon the general style of the typography adopted for the book. In the hands of some contemporary printers the Aldine practice of wide letter-spacing of small capitals has been followed quite skilfully in title- or subtitle lines, chapter headings, and other display work. This is of particular advantage with the rather heavy-faced modern types, i.e., Scotch, Bodoni, etc.
It is well to avoid too many, and too open letter-spaced lines in any kind of display composition, for the effect is sometimes disastrous. Baskerville was very fond of letter-spacing and most of his work is, in that respect, extremely ugly.[37] He sometimes pushed spacing to the point of absurdity; notably in his great Bible, where in the heading of the Book of Job he set the letters J O B in capitals of about 48-point size with three inches of space between them. It could hardly be called a word, but rather just a bad job of type-setting.
The practice of letter-spacing to produce blocked-out lines of capitals must be done with great caution and skill or else a very uneven texture will be produced. Frequently it is better to abandon the idea of a block of type if the spacing cannot be done with a fairly uniform effect. It is a mistake to start with a determination to produce a block of type and then to persist in it at any cost of legibility or appearance. When lines of capitals are set without leading, letter-spacing should never be used. The leading should be in proportion to the spacing in order to keep the continuity of the lines of type, otherwise you will produce columns of letters instead of lines. It is hardly necessary to say that the best letter-spacing is not done with uniform spaces between the letters. The spacing on either side of a letter should be determined by the shape of the adjacent letters. Most compositors have now learned to use spaces according to the shape of the letters, but the cutting of such letters as V, W, to make them set closer than their natural width is usually very much overdone. The new logotypes cut for this purpose are equally faulty in this respect. The resulting effect is more noticeable and more objectionable than the natural setting of the type would be. Anything that strikes the eye as strange or unusual in a line of type is to be avoided.