After wetting the etched stone, he could roll grease-based ink over it. The etched
areas of the stone (i.e., the desired image) retained the ink, while the un-etched,
or negative, areas repelled it. Paper could then be laid down on the inked
limestone block, put through a press, and the inked image would be transferred
to the paper.
The limestone block could be re-used countless times to print the image. When
the printer wanted to change the image, all he needed to do was to sand down the
etched layer and re-start the process on the limestone block. Thus, Senefelder
discovered the first planographic printing process (i.e., printing from a flat
surface as opposed to a raised or incised surface) that was put to commercial use.
Lithography not only allowed easy mass-production of posters for commercial
reasons, but also helped turn the poster into an accepted and popular form of art.
Lithography is taught in art schools today as its own art form. Some of the most
well-known artists to utilize the poster as an art form are Henri Toulouse-Lautrec
and Alphonse Mucha.