How Stone Lithography WorksEver since man first created his earliest works of art thousands of years ago, there have been two parts to the artistic process. The first part happens in the artist's mind, where he or she conceives of the idea that will be portrayed in the work. The second part happens in the artist's hands, as the idea is translated into a specific medium that other people can appreciate. Visual mediums can be quite diverse and include:

Charcoal on cave walls (one of the earliest mediums) Charcoal, crayon, pencil, watercolor or ink on paper Oil paint on canvas Paint on wet plaster (fresco)

(We've ignored sculpture, music, dance, film, etc. and have focused on visual media that are comparable to the topic of this article.)

When the printing press first appeared on the scene, it opened up a new medium in the form relief prints. The artist could carve an image onto wooden or metal blocks, ink the block and impress it on paper. Relief printing created the first form or reproducible art.

The problem with relief printing is that the artist must carve the image, and the carving action is unnatural to an artist who normally works in a medium like paint and pencil.

Stone lithography was the first printmaking technology that allowed a traditional artist to work using traditional techniques, and to create prints that could rival an original painting in terms of detail, mood and color variations. Stone lithography was popular for about a century during the 1800s, and is still practiced today by artists and lithography studios.

Let's start by learning how you can use stone to put ink onto paper.

The Basic IdeaStone lithography was invented in 1798, and it was the first new printmaking technique to emerge in about 300 years. Stone lithography became very popular as a medium by the 1830s. People used stone lithography to create color art for books, as well as for more pedestrian things like labels, flyers and posters.

Stone lithography's popularity with artists came about because it was the first printmaking medium to allow the artist to naturally "paint" or "draw" onto a flat stone to create an image. The artist creates the work directly and naturally.

Photo courtesy Toby Michel

Artist Peter Alexander at work on a stone

The basic idea used in stone lithography is extremely simple:

1. The artist draws/paints on the stone with a greasy substance. For example, a litho crayon is a soft waxy/greasy crayon. There are also litho paints and pencils. The stone picks up this greasy substance and holds it.

2. The stone is moistened with water. The parts of the stone not protected by the greasy paint soak up the water.

3. Oil-based ink is rolled onto the stone. The greasy parts of the stone pick up the ink, while the wet parts do not.

4. A piece of paper is pressed onto the stone, and the ink transfers from the stone to the paper.

As you will learn in this article, the details of preparing and inking a stone to create a print is far more involved than this, but that is the basic idea.

To get a better idea of how stone lithography works in the abstract, imagine the following:

1. Take a piece of paper and paint a stick figure on it with linseed oil (or common vegetable oil).

2. Now moisten the rest of the paper by misting it with water. 3. Put some oil paint on a cotton ball and dab it onto the paper.

The parts of the paper moistened with water will not pick up any of the paint (oil and water repel).

The parts of the paper coated with linseed oil will pick up the paint. This sheet is now "inked."

4. If you now press another piece of paper onto the inked sheet, the painted portions will transfer to the new sheet of paper and create a print. You can re-ink the original sheet to create multiple prints.

The essence of the technique is the affinity of oil for oil and the repulsion of oil and water. In stone lithography, you use a flat limestone block when you create the original image.

Preparing the StoneThe 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.

Lithography TodayLithography is incredibly common today -- it is used to print nearly every book, magazine and newspaper you see (check out How Offset Printing Works for details). The modern version uses aluminum plates rather than stone, but it's the same principle.

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."

The ArtistThe artist uses litho pencils and crayons, as well as a greasy liquid called tusche, to create the image on the stone.

Photo courtesy Toby Michel

Litho pencils, litho crayons, tusche and brushes -- the basic tools of an artist working on a stone

Litho pencils are waxy and range in hardness from 0, which almost melts in your hand, to 7, which is brittle.

Peter Alexander is a well-known artist who lives in Los Angeles, CA. Peter has created a sketch of his piece and uses it as a guide as he is working on the stone.

Photos courtesy Toby Michel

As the tusche dries, it reticulates. Net-like features are left on the stone and show up in the final print, a characteristic unique to stone lithography.

From the artist's standpoint, you can see that the process of preparing the work is extremely natural. There is not a tremendous amount of difference between drawing/painting on the stone and doing the same on a piece of paper. There are a few things to keep in mind, however:

Anything that involves lettering has to be drawn on the stone as a mirror image. Anything that involves multiple colors must be color-separated in the artist's mind,

and the artist must prepare a different stone for each color. The printmaker must then ink, align and press the paper on these separate stones to create the final image. A complex image can have seven or eight stones.

Erasing a mistake is difficult, and a large mistake means starting over. Because there is little or no way to correct a mistake, Toby says, "The artist has to be willing to fly." Some artists, like Peter, create their entire work in an hour or so. Others spend days at a stone.

Etching the StoneOnce the artist finishes, it is time to etch the stone to prepare it for printing. The process of etching fixes the artist's image on the stone -- makes it a part of the stone, in reality, through a chemical reaction involving nitric acid.

Photo courtesy Toby Michel

Etching chemicals and tools include gum arabic, nitric acid, rosin, talc, brushes, cloths and protective gear.

The process is described in the following photos.

Rosin protects the finer details of the image from the acid, so they do not burn out when the acid is applied. Toby sprinkles on the rosin...

...and brushes it down tight on the stone. He does the same with talc.

A solution of 4 ounces (113 g) of gum arabic combined with six to seven drops of nitric acid is prepared.

Toby pours it onto the stone...

Photos courtesy Toby Michel

...and brushes it on. The solution is applied more heavily on the dark areas and hardly at all on the light areas.

The nitric acid reacts with the grease (oleic acid) to create oleomagnate of lime. The image literally becomes part of the stone. In the process, the acid sensitizes the dark areas so they accept ink and reject water, and desensitizes the light areas so they reject ink and accept water. Both the sensitization and desensitization happen in one step.

Toby buffs the gum arabic down with cheese cloth, using perhaps eight cloths in five minutes, in a process that is "like waxing a

dining room table."

After it dries, Toby wipes the stone with paint thinner.

Photos courtesy Toby Michel

In this photo, you can see that the image has "gone gray" and become part of the stone. Toby rubs in asphaltum, a naturally occurring

petroleum substance that seeps out of the ground in certain areas. It is a thick, greasy fluid. This gets a greasy substance into the image.

Next we'll find out about inking the stone.

Inking the StoneThe next step is to move the stone to the press and ink it for the first time.

The stone moves onto the press.

The ink is thick enough that you need a spatula to apply it.

Loading up the ink roller with ink

Toby applies water to the stone and has to work very quickly at this point. The water will dissolve the gum arabic and reactivate the acid, so he must

get the water off as soon as possible.

Wiping off the water with a sponge: The non-inked parts of the stone remain moist.

Preparing to ink

Photos courtesy Toby Michel

Applying ink for the first time: Toby will spend 30 to 45 minutes on the first inking. It is very light so that he doesn't fill in the image.

According to Toby, you would never pull a proof at this point. He will re-etch it and let it sit overnight.

ProofsThe day of the first proof is important for both the printer and the artist. All of the work of the past several days comes down to this moment. Here's what happens.

Toby washes down the stone.

Toby inks the stone.

The first proof is done on a sheet of newsprint.

Toby lays the tympan down over the paper to protect it from the press.

The press rolls the stone, applying 2,500 to 2,700 psi to the paper.

Photos courtesy Toby Michel

Tony pulls the first proof. It is very light. Five to 10 subsequent proofs will darken until the stone is ready for printing.

If the image has multiple colors, the artist creates multiple stones (one for each color). The printmaker repeats the printing process for all of the stones. See The Curwen Studio and Artchive.com for nice demonstrations of the techniques used in multi-color prints.

CorrectionsToby and Peter now examine the proof.

There is a line in the proof that Peter does not like, so he removes it using sandpaper, as shown below.

Using sandpaper, Peter removes the line. Obviously, the amount of correcting you can do in this way is limited.

Photos courtesy Toby Michel

The artist and printer collaborate on final changes.

The stone is now ready to create prints.

Creating Prints

If inked properly, the stone is good for 100 or 200 prints. Peter Alexander normally limits his print runs to a much smaller number. Of Peter's Cat Series, only 25 prints are available.

Making an official print requires several steps:

The first step is preparing the paper. Large sheets are torn to size.

Photo courtesy Toby Michel

Tearing the paper

Next, registration marks are put on the paper. Marks were placed on the stone before the artist started working. Marks in corresponding positions on the paper make sure that the paper lines up with the artist's image correctly. Registration marks are especially important on multi-stone prints so that all of the colors line up.

Adding registration marks

The stone is inked and the print is made using the process described on the previous page.

A copy of the final proof of "3rd Street," by Peter Alexander, 29.5" x 35", printed on Rives BFK in an edition of 15, $1,500.00 each (There will also be a "reversed" version of the image

with white ink on black paper.)

The proof receives the "shop chop" in the lower left corner. Every print from Angeles Press receives this mark. Toby has two: A scallop shell is his personal chop, and Angeles Press has a pair of angel-wing shells as its mark.

Photos courtesy Toby Michel

Adding the shop chop to the print

The artist signs the proof.