Drawn in pen and ink, reproduced by process block.

To convert the design upon the zinc plate into a relief block to print with type is only one step farther—to so protect the lines of the design on the zinc plate, as to resist the corrosive action of acid, and by etching the plate, produce a relief block. For this purpose, a resinous or bituminous substance is introduced into the composition of the printing ink. Here, then, we have the lines of the design in an acid-resisting material upon the surface of a metal plate exceedingly susceptible to the action of acids. If the prepared plate is now placed in an acid bath, the entire surface of the zinc, except the protected lines, will become etched, or dissolved away, leaving the design in its integrity, with the lines standing up in relief: the etched plate has now only to be mounted upon wood to the height of type to be ready for the printer’s use.

Pen and Ink Drawing, reproduced by process block.

Pen and Ink Drawing reproduced by Photo-lithography.

Such is a brief outline of the process in the production of Line Blocks. The design may be put on the metal plate in any of the following ways:—