Figure 2 in which the upper line of letters is essentially "Roman Lower-case"; the lower essentially "Italic."
The essential differences are obviously between the forms of the letters. The following letters, abdefghklmnqrtu and y, are not Roman Capitals, and that is all about it. The letters shown in the lower line of Fig. 2 are neither Capitals nor Lower-case. The conclusion is obvious: there is a complete alphabet of Capital letters, but the Lower-case takes ten letters from the Capital alphabet, and the Italic takes ten from the Capitals and twelve from the Lower-case. Figure 3 shows the three alphabets completed, and it will be seen that CIJOPSVWX and Z are common to all three, that bdhklmnqrtu and y are common to Lower-case and Italics; that ABDEFGHKLMNQRTU and Y are always Capitals; and that aef and g are always Lower-case.
Figure 3 shows the differences and similarities between the three "current" alphabets. Note: the curve of the Italic y's tail is due to exuberance, and not to necessity.
But tho' this is a true account of the essential differences between the three alphabets, there are customary differences which seem almost as important. It is customary to make Roman Capitals upright. It is customary to make Lower-case smaller than Capitals when the two are used together; and it is customary to make Italics narrower than Lower-case, sloping towards the right and with certain details reminiscent of the cursive hand-writing from which they are derived. Fig. 4 shows the three alphabets with their customary as well as their essential differences.
Figure 4 shows the Capitals, Roman Lower-case and Italics with their customary as well as their essential differences.
Properly speaking there is no such thing as an alphabet of Italic Capitals, and where upright or nearly upright Italics are used ordinary upright Roman Capitals go perfectly well with them. But as Italics are commonly made with a considerable slope and cursive freedom, various sorts of sloping and quasi-cursive Roman Capitals have been designed to match. This practice has, however, been carried to excess; the slope of Italics and their cursiveness have been much overdone. In the absence of punch cutters with any personal sensibility as letter designers, with punch cutting almost entirely done by machine, the obvious remedy is a much more nearly upright and non-cursive Italic, and for Capitals the ordinary upright Roman. Even with a nearly upright Italic, the mere presence of the Italic aef and g alters the whole character of a page, and with a slight narrowness as well as a slight slope, the effect is quite different from that of a page of Lower-case.
The common practice of using Italics to emphasize single words should be abandoned in favour of the use of the ordinary Lower-case with spaces between the letters (letter-spaced). The proper use of Italics is for quotations and footnotes, and for books in which it is or seems desirable to use a lighter and less formal style of letter. In a book printed in Italics upright Capitals may well be used, but if sloping Capitals be used they should only be used as initials—they go well enough with Italic Lower-case, but they do not go with one another.