American founders have adopted the practice of casting type-faces on uniform lining systems, variously known as American line, standard line, uniform line, etc. The earlier practice was to cast the type of a font so that the letters would align at the bottom only with their mates of the same font, without reference to any other face of type. When the compositor had occasion to use two or more different faces of type in the same line, these faces were rarely in even alignment, but were irregularly high or low, as shown in the accompanying example [a]. This lack of uniformity made it necessary when a different face was used in the line, as is often required in jobbing and advertisements, to use thin leads, cards, or pieces of paper above and below different parts of the type-line in order to get the faces in line—an operation more or less troublesome and expensive. By the modern lining system, the faces made on any given size of body are cast to align with each other, as shown in the second example . These different faces require no more adjustment than if they were all of one font.
On different sizes of type the shoulder, or blank space, at the bottom of the letter increases gradually with the size of the type, so that a word of small type placed beside a larger size must have some spacing material below as well as above to keep it in its right alignment. This necessary difference in the face-alignment of various sizes is graduated by points, in the lining system, so that when more than one size type is used in the same line the justification is made by using point-body leads. This makes the use of slips of card and paper unnecessary and secures greater accuracy and solidity of the composed page.
Faces of radically different style are not, however, all cast on the same alignment, but are classified into three groups. One group embraces the majority of type-faces, those having capitals and small letters, g y p j. Another group embraces fonts of capitals only, mostly faces known as title letters and combination lining faces which, having no descenders, may be made lower on the body. A third group includes those faces having long descenders, like script types, which must be placed high on the body.
A common class of “lining” types for job work are the combination series, or those having two or more sizes of face (capitals only) cast on bodies of the same size. Each face is made to line with the others on the same body, and all the faces are readily used in combination, with a single size of spaces and quads. In order that the type of each face may be readily distinguished, the nicks are varied in number or position—a single nick for one face, two nicks for another, etc.