Leading is the vertical space between set lines of type.

Copy set on a wide measure needs open leading to be readable. Otherwise the eye has trouble following from the end of one line to the beginning of the next.

11 point type with 12 point leading:

11 point type with 14 point leading:

The character of the typeface used is important in making leading decisions. Older faces based on metal designs often have long descenders and ascenders and are designed to be used with open leading. Some contemporary faces, particularly faces created for advertising work, such as ITC Garamond, are designed to be used with little, zero, or negative leading. These faces have short ascenders and descenders and large x heights. They were designed to accommodate art directors’ demands for typefaces which could be squeezed horizontally and vertically in order not to compete with the visual imagery in the ad.

A peculiarity of the desktop publishing era is the use of ITC Garamond with open leading, as if it were an oldstyle Garamond. One way to get ideas for the use of a particular typeface is to review how the designer of the face used it. For example, when considering Centaur one could look at the books designed by Bruce Rogers in that face.

Leading should be internally consistent throughout a publication. The leading from head A to head B, from head B to body copy C, etc., should be consistent from page to page. The use of the mouse with pull-down menus in the "point and shoot" formatting techniques of many desktop publishing programs can result in arbitrary, inconsistent, leading choices. Using multiples of the basic body leading, based on the design of the page grid, adds design unity to a page. Most leading then ends up being one-half line, line, two line, etc.

Next we’ll take a short look at typeface selection.