In this type of print the image is printed from a completely flat surface. It is a chemical process based on the principle that oil and water don't mix but resist each other. Another seldom-used name for this type of process is resist process, There are only two types of prints in this category: lithographs and collotypes (not to be confused with collagraphs). Original lithographs should not be confused with offset lithography. Original lithos are done entirely by hand, while offsets are a common everyday type of reproduction print. Newspapers and magazines, for example, are printed this way. Fine art posters are produced by the offset process as well, but more care is taken in their creation. Sometimes extra color runs are added to improve the quality, but they still remain photo-mechanical copies untouched by the artist's hand.

               Original Lithographs. Lithography was invented by Aloys Senefelder in 1798 and immediately became immensely popular as an artistic medium. In this technique the artist actually draws on a specially prepared flat piece of limestone or a metal plate made of either aluminum or zinc. The artist uses a grease or wax crayon or a greasy drawing ink called tusche to create the image just as if he or she were drawing or painting on a piece of paper. In fact, the way the surface is prepared (it is abraded down to a velvety texture by the use of abrasive carborundum powder) makes the stone or plate feel like you are drawing on a very heavy drawing paper. In the case of stone lithography it is a VERY heavy paper substitute; some stones can weigh as much as 300 or more pounds. Forklifts must be used to move the artist's drawing materials around. Stone lithography has gone out of favor in recent years mainly because of the physical demands involved. Also, a much easier and relatively new process called "mylar transfer" (see below) Metal litho plates are very lightweight and portable, but do not produce as fine an image as stone. A good stone lithograph print is almost indistinguishable from an original drawing. After the drawing is finished on the stone or plate it is then treated with a mixture of gum arabic and dilute phosphoric acid which reacts with the waxy drawing materials to produce a type of water-repellent soap that will accept the oil-based printing ink. During printing the stone is alternately kept damp with water and then rolled up with the oil-based ink. This is another extremely demanding process. If the stone isn't kept damp enough, or the water is either too acidic or too basic, the whole image can be lost irretrievably and all the time spent developing it wasted. The print paper is placed on top of the freshly inked stone or plate. A specially constructed press has to be used not only to bear the weight of the stones, but to support the extreme pressures needed to print the image. Instead of a press with a metal roller on top and on bottom like an etching press, the litho press uses a narrow wooden or plastic scraper bar above in contact with a greased sheet of metal or plastic over the print paper. Pressure of up to two thousand pounds per square inch is applied to this stone, paper, and plastic sandwich as it is cranked by hand through the press. As in most other print media, if more than one color is used separate plates or stones must be made for each color. Each plate or stone must be printed again on top of the previous runs through the press.

      Chromolithographs are lithographs printed in several colors. Chromolithography has existed probably since the early stages of lithograpic printing.

                Collotypes. Not to be confused with collagraphs. In this extremely rare and miserably difficult photographic medium the prints are printed on either a regular etching press or litho press from glass plates (yes, real glass...) coated with a thick gelatin-based photographic silver-salt emulsion. The image is exposed on the plate and developed just as a regular photograph would be using all the same chemicals. But instead of printing the image on light-sensitive paper, the gelatin plate is kept damp in a humidity-controlled room (controlled to tropical jungle levels of humidity) so the gelatin will absorb moisture from the air where there is no black silver image protecting it. Some of the few artists working in this medium go ahead and use sponges very gingerly to keep the gelatin damp because the act of printing works up enough of a sweat as it is without resulting to subjecting the printer to drudge away in a sauna. The plate is rolled up with an oil-based ink which, with luck, sticks to the silvered areas and, with luck, is repelled by the damp gelatin.
Obviously there are many potential drawbacks to this process, the worst of which is the delicacy of the printing surface. If there is just a little bit too much moisture in the air or if the sponge is too damp the whole gelatin surface will dissolve causing the image to simply peel off the plate. Another problem is the pressure of the press. If there is any irregularity or bump in the press bed, or if too much pressure is used on the glass plate... well, you know.

This category includes mostly those types of prints intended to be used as posters, although some artists are producing hand-drawn offset lithographs in small, limited editions and other artists are experimenting with hand manipulated and modified color copies as original prints. The Printmaking Police don't always accept these as originals, however. There are just as many printmaker purists out there as there are experimenters. Very few prints produced photo-mechanically can actually qualify to be called original prints, though. The element of the artist's direct control and manipulation of the medium is missing.

                 Offset Lithographs. These are the prints that comprise the bulk of the poster market. They are inexpensive to print in large quantities so they can be sold at affordable prices. Original prints are very labor-intensive and therefore often sell for hundreds of dollars each, placing them out of the financial reach of most potential art collectors. The process is the same in principle as in an original lithograph, but offsets are printed on huge, high-speed mechanical presses often in quantities of thousands of prints at a time. A big technical difference between the two media is the concept of offset printing. In an original litho the stone or plate is inked up and then printed directly on a piece of paper. In the offset process the plate prints, or offsets the image onto a rubber roller and then the image is printed from that onto the paper. This causes a double reversal of the image, so the plate appears just as the print will appear. The image on the plate is not a mirror image of the final image as in the other print media (with the exception of the stencil processes)
If you look very closely at an offset poster print you will see a regular pattern of colored dots, similar to the dots in color comics in the newspaper. The dots are called a "half-tone screen" or half tone for short. The only way to reproduce the colors of the original artwork that was photographed is to break down the colors into four components, the "four-color process", sometimes called the Pantone process. The four primary colors in offset printing are magenta, cyan, yellow, and black. If you look closely at the dots you will see that they are printed only in those four colors. By printing the dots larger or smaller side-by-side with the other colors the eye is fooled into seeing the mixed secondary and tertiary colors. The more dots per square inch, the better (and more expensive) the print, but it's still an offset and not an original print. Original hand-drawn lithographs do not have the half-tone dots, unless for some reason the artist chose to use a photo process in part of the image. In an original print each color is mixed by hand and is printed separately, and even under a microscope the drawing looks like a drawing, not a comic-book page.

                    Mylar Transfers. It is possible to produce a sort of hybrid hand-manipulated offset print, however, using the "mylar" process. In this technique the artist draws the image on a sheet of transparent mylar plastic. The image is then exposed on a photo-chemically coated aluminum offset plate and then printed. Some people consider this a type of original print, but in this artist/printer's opinion it blurs the distinction between "original" and "copy" since there is no need for knowledge of or experience in the lithographic process by the artist who is doing the drawing. This process is a very useful shortcut to getting precise registration of color in multiple plate images, however, and an added benefit is that the artist does not have to draw the image backwards as in the traditional process. A mylar transfer lithograph has no halftone as a photo-mechanically produced poster would, and is almost indistinguishable from a lithograph drawn by hand on a plate.


                Color Copies. Many artists are experimenting with color copy machines as an additional tool for producing an image. Theoretically, original prints cannot be produced in this manner because of the lack of a matrix made by the artist that physically produces the image. The copy machine does just what it says. It makes copies, not originals. However, a copy can be the basic image which the artist then adds to and modifies into a mixed media print.

                     Giclée Prints are another type of color copy produced with the aid of a computer on a large, special color plotter. Like other color copies they are not originals and can be printed in quantity or one at a time. Unlike offset lithographs however, they do not have the half-tone dot pattern, but a smoother and random array of tiny dots of color.