The Composition Caster automatically composes text ready for the press. No longer keyboarding a punched paper tape (think piano roll), the Welliver system reads a digital file and instructs the caster to cast type in any order, along with spacing material as required.

Type can be made from 4 point to 24 point in composition. Generally speaking, “small composition” runs from 4 to 12 point (although in some cases up to 16 pt), and “large composition” runs from 13 pt to 24 pt. The main difference concerns the size of the matrices. Small comp mats are 0.2” x 0.2”, and large comp mats run 0.2” x 0.4” and 0.4” x 0.4”. When running small comp above 12 pt, a special “doghouse” mold is used. This results in a tapered body near the face, leaving some of the face to overhang the reduced body size just below the face. Thus 14 pt small comp doghouse type has an overhang of 2 pts for the face (1 pt at the top of the character, 1 pt at the bottom), although the face itself does not go beyond the edges of the full body.

When type face matrices come as composition matrices, fonts can be cast in composition as well as any text.

Since this is Monotype, each character has its own body, unlike Linotype or Ludlow, which are slug casters. Slugs carry many characters, so that changes to the text cannot be made without making a new slug. With monotype, changes can be made easily by removing some type and placing new type into the form. Monotype metal is also harder than Linotype or Ludlow, although not as hard as true foundry type.