How are Color Lithographs Made?

Question

I've heard that an artist makes a color lithograph by using more than one stone. How does this work in practice? Does the artist really need to paint on 6 different stones to create a painting with six colors? How does the artist know how the print will look once the stones are combined when transferred onto paper?

Answer 1

You don't paint on the stone. You draw on it (or make marks in some way, so I suppose you could "paint" with the tusche) with a waxy or greasy pencil (or substance). Once that's done, you use gum arabic and nitric acid to "etch" the stone, but all that really happens is the areas with the greasy or waxy substances applied are conditioned to attract oils, the exposed areas of the stone are conditioned to attract water.

The artist may use many stones to do a print. In most commercial printing processes (in which you wouldn't find a litho stone, but rather offset plates), the most likely scenario would be 4 or 5 stones: The primary ink colors (cyan, magenta, yellow, and black, or CMYK) and possibly a spot color (maybe more than one).

In most printing processes, the artist would putt a proof to check the stone, however, lithography is very touchy (at least the artistic lithography- I've never printed in a commercial setting). Once the stone has been printed, it will continue to deteriorate. You can recover it, but it requires reetching and going back to almost step one. Most likely, the artist would prepare in advance and have very accurate registration marks set up and have planned the print very very well in advance.

I'm sure there are major differences between lithography as an art form and lithography as a commercial printing process, but since you asked about stones, I'm assuming your interest is more in the art form.

Answer 2

Lithography usually does not involve painting on stones although one form involves using a greasy pencil. It involves etching the stones so part will hold ink and part will not. Therefore, the technical people doing the lithography judge how to separate the colors and make anywhere from a few to a couple of dozen stones, each of which takes one color of ink. There are often exhibits at museums showing all the stones and colors and the development of the piece as colors are added.
The artist sees the results by the printers pulling proofs. Marks on the stone and on the paper align the paper to printing matches from stone to stone.
Painting on a stone (other plate) is called monotype.
http://www.lib.udel.edu/ud/spec/exhibits/color/lithogr.htm
http://www.unm.edu/~tamarind/definitions.html