Lithography quickly grew in popularity with artists because it was the first printmaking medium that allowed them to closely mimic the process of drawing or painting. Quite spontaneously, the artist could draw onto a flat stone to later create an image.
The actual details of preparing and inking a stone to produce a print are far more intricate than it seems, but the following is the basic process.
A flat, smooth stone (such as limestone) is used as the “canvas” for a drawing. The artist draws on the stone with a greasy substance such as a litho crayon or special litho paint. The stone then absorbs this oily substance and holds it in place.
The stone is then brushed with a thin layer of water. The water is absorbed in all the areas where the oily crayon is NOT present. The principle being that oil repels water and thus later the ink will be deposited on the oily part of the stone to be picked up by the paper.
At this point an oil based ink is rolled on to the stone. The oily parts attract the ink and they stick to each other. Conversely, the water repels the oily ink. A sheet of paper is then pressed on to the stone and the ink left on the stone is transferred to it by means of even pressure. If the image is meant to contain multiple colors, multiple blocks are used, one for each color.
The best stones used for lithography come from a quarry in Solenhofen, a town in Bavaria in Southern Germany. These slabs are often reused mostly due to their high cost. The process of recycling the stone is quite laborious and the first step is to grind the stone to remove the previous image. Afterwards, the stone is carefully polished to prepare it for the next artist or the next image.
A large stone can weigh up to 1,000 pounds (454 kg). They are usually moved around the studio with the aid of a lift truck. The grinding of a previously used stone is done with a tool called a levigator. A levigator is a rather simple tool consisting of a heavy steel plate with a handle on it.
The first step in reusing a stone is to check the flatness of the stone. Using a steel straight edge and a sheet of paper the artist will take note any high or low spots and attempt to remove them during the grinding process.
The artist then dusts #80 carborundum grit onto the stone and begins grinding with the levigator. The grit will only last three to five minutes before it loses its cutting power and it needs to be washed out and replaced. It takes several hours to remove a mere millimeter off the stone’s surface.
Since a lithography image is printed off the top ½ millimeter of the stone, it is essential to be very thorough during this part of the procedure. A deficient grinding will leave a ghost of the previous artist’s work and that ghost will come through in the new image.
In what is a very lengthy method, the artist proceeds to polish the stone with progressively finer grits. Starting with #80, following with #100, then #180 and finally #220 grit, the artist makes every effort to put the finest tooth on the surface.
A great deal of water must be used to wash everything meticulously in order to get rid of every grain of grit. One single grain of #80 grit could ruin the final print. The stone, the levigator, your hands, your apron and even the surrounding area must be carefully washed.
Once polishing is complete, the artist will move the stone from the graining sink onto a roll table in the studio so that the artist can begin his work.