The term lithography comes from
the Greek words for stone and writing.
The
process of lithography was invented in the 1790’s
by Aloys Senefelder in Munich, Germany. Senefelder,
an impoverished writer, was trying to develop
an inexpensive way to publish his plays. After
accidentally discovering the effects of greasy
ink on limestone, he patented the process and
spent the rest of his life perfecting it. Today,
lithography is used for the commercial printing
of magazines and posters as well as fine art works.
The principle of lithography is
that grease and water repel each other. In lithography,
the artist draws on a stone or aluminum plate
with a greasy crayon or with tusche, a liquid
grease. Lithographic stones can be used over again
by resurfacing or graining the stone with carborundum
grit. Plates can also be made light sensitive
and used with a photographic image. The drawing
is processed with a slightly acidic etch, consisting
of gum arabic mixed with drops of nitric or phosphoric
acid. The drawing becomes hardened and the surface
of the stone becomes desensitized to grease. The
etching process leaves a gum Arabic mask around
the drawing. The drawing is washed out with lithotine.
The gum Arabic does not wash away because it is
water-soluble. Ink is then rubbed into the drawing,
and the gum is washed away. The stone or plate
is kept moist with a wet sponge while the printer
rolls up with an inky roller. The ink, being greasy,
attaches itself to the drawing and not the clear
areas, which are wet and repel the grease.
When
the stone or plate is rolled up with ink, the
printer lays a sheet of paper over the stone.
A thin sheet of plastic called a tympan goes on
top. A bar coated with leather or Teflon is pulled
down onto the tympan with enormous pressure. When
the printer turns a crank, the bed of the press
moves, the bar slides over the tympan, and the
image gets transferred to the paper.
Artists were attracted to lithography
for it’s resemblance to charcoal drawing.
Honoré Daumier, Henri de Toulouse Lautrec,
Winslow Homer, Pablo Picasso and Jasper Johns
are among the many artists who have made lithographs.