Page:De Vinne, Invention of Printing (1876).djvu/31

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Surface Exposed to Impression by the Copper-plate Method.

The entire surface of the plate is covered with ink until the white lines are filled. The surface around the figures is wiped clean before the impression is taken.





Surface Exposed to Impression by the Lithographic Method.

This surface is rolled twice: once with water, which is absorbed only by the surface here shown in dull black tint; once with ink, which is retained only on the figures.