Basic process
Lithographic stone is natural and very water
permeable. It is very finely grained limestone, which can be easily
sanded down and offers a smooth or slightly stippled surface as desired.
The artist draws the picture on the stone with some greasy material or
with lithographic ink which can be applied with a nib or a brush. After
the picture has been created, a solution made of nitric acid and of
arabic gum is applied in order to fix the image on the stone. The stone
is then washed and ink is applied with a roller. The greasy picture
retains the ink while the stone's wet surface rejects it. Color
lithography is a more complex process that usually involves multiple
applications, one for each colour in the picture.
A good knowledge of colour and perfect vision are
necessary.