Matrix monocular optical depth testing instrument

The Monotype Corporation Limited; British Indicators Limited

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Matrix monocular optical depth testing instrument
Science Museum Group
© The Board of Trustees of the Science Museum

Matrix monocular optical depth testing instrument, Plant No.2351, made by The Monotype Corporation Ltd., Salford, Redhill, Surrey, 1957. The instrument is fitted with a ‘John Bull’ dial micrometre by British Indicators Ltd. Used in the production of Monotype matrices to measure the depth of letter characters.

There are 82 separate processes needed to transform a designer’s drawing (of a letter, figure, punctuation, or symbol) into a piece of Monotype metal type for printing. A pantograph is used to trace and cut the letter from a copper pattern into a piece of steel called a punch. After being hardened, the punch is driven into a piece of bronze using a crank press to produce a matrix. The finished matrix is ready to go to the Monotype Composition Caster where molten metal is pumped through a mould against the matrix to produce a piece of type.

This machine is one of many machines used in the process to make a 0.2 inch or 0.4 inch matrix.

The Type Archive has a functioning Monotype matrix workshop containing around 70 machines and pieces of equipment. It is the only one of its kind in the world and matrices are still produced for customers.


Printing & Writing
Object Number:
aluminium alloy, bakelite, copper (metal), pine (wood (unidentified)), plastic (unidentified) and steel (metal)
  • tools and equipment
  • equipment

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