Lithography is a printmaking process that employs the concept that water is repealed by wax. Traditional lithography uses limestone to work on. In some more modern concepts the stone is replaced with metal surfaces. But for this explanation and because I use the more traditional technique the examples will be those using limestone. For my process the stones are around 75 years old.
The stone is “etched” with an acid that makes its surface more porous. In this case more porous to water.
The area of the stone to be use to draw the image(s) upon is the porous area. Because not all of the surface of the stone will be use for the drawing the area around the porous portion is covered in a mixture of gum- arabic. That mixture will prevent either the water or the ink from being absorbed into the stone during the printing process.
The image for the print is drawn onto the porous area of the stone using charcoal. Because this is a printmaking process all of the drawing is done in reverse of how the image(s) will appear on the final print. At this stage the charcoal drawing is only an outline drawing. The different values, areas of light and dark, will be added during the third step of the process.
Using lithographic crayons which are a wax based material the different values are added to the drawing on the stone. The lithographic crayons, like drawing pencils, have differing numbers associated with their levels of lightness and darkness. The lower the number, “4” for example, is a darker value than a number “5” crayon. This is a bit deceptive however, because, the number actually identifies how much ink will be absorbed into the area covered by the wax of the crayon rather than the crayons actual value. This will be explained further as we go along.
In these two examples the drawing, using the charcoal lines as guides, is completed by applying the lithographic wax crayon to the composition.
The necessary materials to print are ink, and ink roller, a sponge and two vessels of water.
Step Five: Printing The Image.
The printing process itself is broken up into a number of stages:
The first stage in the printing process begins by removing all of the visible pigment from the stone. Because the image is printed using ink, the pigment that is mixed into the wax of the lithographic crayon must be removed so that it will not interfere in the wax being able to absorb the applied ink.
At the conclusion of this process is appears that the image is gone from the stone. However, the areas of wax that were visible because of the pigment in the wax at the time it was applied to the stone remains on the stone, albeit, unseen. Depending on the individual printers preference some printers, this is a process I use, add liquid asphalt to the stone to re-image the surface. This helps in the application of the ink during the printing process:
The second stage of the printing process begins by placing the stone onto the printing press. The type of press use is called a “scraping press.” The bed of the press moves in a lateral motion using a crank that can be seen on the left had side of the press in this photograph. The bar, seen on the top of the press established the pressure and the stone. With paper placed onto of the stone and protective surface placed atop both the paper and the stone, the stone is pulled under the center bar of the press, seen in this photograph as a small white protrusion. This pressure forces the ink on the stone onto the paper.
In this example my colleague Professor Harry Heil is tightening the pressure of the press.
Once the stone has been placed on the press, the third stage in the printing process begins. The entire surface of the stone is covered in a layer of water. The excess water is removed using a sponge. On the porous areas of the stone that have not been covered using the Lithographic wax crayon the water remains on the surface of the stone. In those areas that have been covered with the Lithographic wax crayon the water is reeled. Once the excess water is removed the ink is applied to the stone using the ink roller. We call this process “charging” the roller.
The roller is used to ad several layers of ink to the stone. The amount of ink required to print a successful series requires that the stone be ” brought up” to a proper printing capability. This requires that the stone is “charged.” The charging of the stone with ink establishes the areas of light and dark, the compositions values. In those areas covered by a lower number Lithographic crayon, number 2 for example, there is actually more wax, a more dense area on the surface allowing for more ink to be absorbed into the wax resulting in a darker area of the composition. In those areas where a higher number, 5 for example, is used there is less wax allowing for less absorption of ink producing a lighter area on the print.The lightness areas of the composition are those where no wax has been placed on the stone surface. In that instance the water that was applied at the beginning of the process repels all of the ink resulting in the lightest areas of the composition.
The stone is then pulled through the press. In almost all instances the first attempt is never of a printing quality. In most instances the print is to light for the series. To make sure that the print is of a satisfactory quality each step in the printing process, washing the stone, charging the stone with ink and printing the image is repeated until the desired quality is achieved. Although most of these attempts are discarded some may be saved and they are identified with the letters AP for Artist’s Proof. These are never considered part of a limited edition series of prints.
The fourth stage of the printing process begins once the desired value quality is achieved. For each print the process of washing the stone, charging the stone with ink and running the stone and paper through the press is repeated.
When a print is identified as being a limited edition print the artist is saying that only a specific number of prints have been made. That identification is added to the print, after the printing process has been completed and at the time the artist signs each individual print. The identifying number is written like a fraction, for example 1/12. That means that no more than twelve prints were made and this number 1 was the first of the twelve to be printed. Because it is impossible to print two prints exactly the same the numbering system established each as a unique creation in and of itself. To make sure that no other prints are made from the stone, the image on the stone is “erased”
Abrasive material, not unlike the abrasive used on sandpaper is placed on the surface of the stone.
A second stone is place face down (the image surface of each stone) onto the first stone and they are then ground together until the image is removed for the surface of each stone.
At the conclusion of the process the images on both stones have been removed and the stone is now ready to begin the process again.