Monotype Casting

Linotype casts a line as one slug. Monotype casts single characters. Write down one advantage and one disadvantage of each before building.

Real type metal is a lead–antimony–tin alloy. Lead is a cumulative poison and casting it is not a classroom activity. This blueprint casts plaster of Paris instead. The mould geometry, the matrix, and the justification arithmetic are identical; only the material changes.

Carve a single letter, in reverse, into the rubber sheet about 3 mm deep. This is your matrix — the female form the type is cast against.

Make a small open box from card, one wall movable. The matrix forms the base. The movable wall is the point — Monotype's mould changes width for every character.

Set the movable wall to 8 mm. Record the setting.

Mix plaster to a pourable cream and fill the mould. Level the top.

Wait 15 minutes, then flex the rubber matrix away. You have a single piece of type with a raised reversed letter.

Reset the movable wall to 6 mm, 10 mm and 12 mm and cast three more. Real type is proportional — an 'i' is not as wide as an 'm'.

Sand each casting flat on its back and sides so all four stand at identical height.

Measure each type body. Record the four widths. These are your character set widths.

Choose a line length of 120 mm. Add up your character widths for a short sentence. Subtract from 120. Divide the remainder by the number of spaces. That quotient is what every space must be widened by — and Monotype had to know it before it cast the first character of the line.

Set the mould to the width you calculated and cast the spaces.

Assemble types and spaces in a card channel. Measure the finished line. It should reach 120 mm within a millimetre.

Pull a single type out and replace it. Note that this took seconds. On a Linotype it means recasting the whole line — the entire argument for Monotype in one action.

Roll ink over the assembled line and press paper onto it.

US 557,994, “Machine for making justified lines of type”, Tolbert Lanston, granted 7 April 1896. Patent protection ran 17 years from grant and expired in 1913.

Lanston, of Washington D.C., applied in 1885 for a typesetting system that produced its printing surface by cold-stamping rather than casting, and demonstrated a prototype in 1887. The hot-metal machine of this 1896 patent is the mature form. Sources disagree over whether to date the Monotype to 1885, 1887 or 1896 because they are describing three different things — the application, the prototype, and the casting machine.

A note on the record. Google Patents shows the filing date for US 557,994 as identical to the grant date. That is a cataloguing artefact, as with Hawes's envelope machine in this same batch; cite the grant date only.

How the real machine split the job in two. Monotype used two separate units — a keyboard that punched a paper ribbon, and a caster that read it. The operator typed; the ribbon was carried to the caster; the caster read the ribbon backwards, which is why the justification had to be computed and recorded at the end of each line as it was keyed. This is a genuine ancestor of stored-program control: an operator producing a physical instruction tape consumed later by a separate machine, in the same family as Jacquard's cards and Hollerith's punched strips.

Monotype outlived Linotype in fine bookwork precisely because of single types — corrections were cheap and the typographic quality was higher. Both were finished by phototypesetting and then by digital composition.