How Stone Lithography Works

Preparing the Stone

The first step in creating a print using stone lithography is to prepare the stone for the artist. Toby selects a flat limestone block of the appropriate size. If the image will contain multiple colors, multiple blocks are used, one for each color. The best stones come from the quarry in Solenhofen, a town in Bavaria (see Printmaking dictionary: Lithography for details).

Stones are reused, so the first step is to grind the stone to remove the previous image and then polish the stone to prepare it for the artist. The following photographs show you the process.

A large stone can weigh up to 1,000 pounds (454 kg). Toby moves it to the graining sink (on the right) with a lift truck.

The grinding is done with a tool called a levigator. As you can see, the levigator is simply a heavy steel plate with a handle on it.

Using a steel straight edge and a sheet of paper, Toby checks the flatness of the stone. He will note any high and low spots and attempt to remove them during grinding.

Toby spreads #80 carborundum grit onto the stone and...

...starts grinding with the levigator. The grit will last three to five minutes before it loses its cutting power.

Photos courtesy Toby Michel
Every five minutes or so, Toby washes off the worn grit and replaces it with new grit.

A lithography image lives in the top 1/64th of an inch (about half a millimeter) of the stone. Grinding takes several hours on a large stone like this and will remove about a millimeter of the stone. If not enough stone is removed, it leaves a ghost of the previous artist's work, and that ghost will come through in the new image.

Once ground, Toby polishes the stone with progressively finer grits, moving from #80 to #100, #180 and finally #220 grit, to put a fine tooth on the surface. According to Toby, "One grain of #80 grit will sabotage you once you start polishing -- you use a lot of water and wash everything meticulously to get rid of every grain of grit. The stone, the levigator, your hands, your apron all get washed." Polishing a large stone can take three to five hours.

Once polishing is complete, Toby moves the stone from the graining sink onto a roll table in the studio so the artist can begin his work. One of the more interesting problems in stone lithography, especially on large prints, is "moving the stone." This block weighs about 600 pounds.

Photos courtesy Toby Michel

In Toby's experience, moving the stone "is best done by one person, despite the size: A lack of coordination can lead to smashed fingers or worse."