Lithography, while a simpler and less expensive mode of making stamps
than those previously described, is not often employed for the purpose.
The work is inferior in quality and too easily counterfeited to commend
itself. In lithography the lines of the design are neither sunken nor,
to any appreciable extent, raised above the surface. The design is
practically a drawing, in a certain greasy ink, upon stone of a
particular quality. When several colors are used, as in
chromo-lithography, a separate stone is prepared for each. The design is
sometimes drawn directly on the stone and at others transferred to it.
For stamps a die is made in wood, metal or stone. Impressions from this
are made in transfer ink (a very "fat" ink, made of soap, resin, tallow,
etc.) upon transfer paper. These impressions are placed, face downward,
on the stone and the paper is moistened. On being passed through a press
the ink adheres to the stone and the paper is easily removed. A wet
sponge is passed over the stone, the water adhering to the exposed
surface but not to the greasy ink. While it is moist a roller, covered
with transfer ink, is rolled over the designs to which it adheres. The
wetting and rolling are alternated until the designs have sufficient
body. Lastly, a very weak solution of nitric acid, gum arabic and water
is passed over the stone. This is at once washed off. It bites the stone
to a very trifling extent and serves to clean the surface and add
sharpness to the design.

Impressions taken from a lithographic stone are perfectly flat and
smooth, the surface of the paper being neither raised nor depressed.
They have usually a slightly greasy feel.

[Illustration, Stamp, "N. Caledonie", 10 c.]

An interesting specimen of lithography is supplied by the first issue of