Writer and photography / Angela Young
Angela Young describes the background of photolithography and shows, step by step how to make a print.
Alois Senefelder invented the printmaking process of lithography in 1798. From its beginning, according to the College of Technology’s Digital Media Program’s article The History of Lithography, it has become one of the largest industries in the United States – a part of the Printing Industry, which is the third largest manufacturing industry in the United States.
Alois Senefelder started out his career as a successful playwright. Several of his works were published; however, he found it expensive to reproduce copies of his plays. In an attempt to reduce the publication cost, he tried to produce his own copperplate engravings. In the late 1700s copper plates were mostly used in printing, but it was a difficult process to create images and text to be printed in reverse (Jezek 1). In order to reduce cost and time, Senefelder decided to practice his engraving on slabs on Bavarian limestone instead of expensive copper. To correct mistakes made on the limestone, he found that a mixture of wax, soap, lamp-black and rainwater were efficient (The History of Lithography 1).
Through experimentation, Senefelder discovered that when he drew on the limestone with the correction fluid, the drawn image would repel water, while the surface of the stone where no image was drawn would hold water.
“He found he could first wet the entire stone then apply ink, with a roller, to the entire stone to replenish the ink on the image”
(The History of Lithography 1). The stone itself, which held water, would repel the ink, and the correction fluid, which is greasy and repels water, would accept more ink. Since lithography is based on a chemical principal, Senefelder decided the call the process chemical printing.
In 1826, Joseph Niepce, a French scientist, produced the world’s first photograph. This discovery eventually lead to the use of the halftone process (the act of breaking down the original photograph into dots of varying sizes that would be suitable to press reproduction). Henry Talbot used the first halftone screen used for the reproduction of photographs around 1852. About 33 years later, Frederick Ives, an American, designed the first practical halftone screen that consisted of two exposed glass negatives with line scribed on each of them. They were then cemented together so that the scribed lines would cross at right angles (The History of Lithography 2). This halftone process allowed the reproduction of original photographs without the need to draw or engrave them onto a printing plate.
Photolithography is a process by which images are photographically transferred to a matrix (either an aluminum plate or, less frequently, a stone), and then printed by hand (Devon 183). The French printers Alfred Lemercier and Alphonse Poitevin first started experimenting with photolithographic techniques in soon after the discovery and use of the halftone process. Their early experimentations, however, were not reliable enough for commercial use. Photoengraving was the industry standard until offset lithography became commonly used for reproduction in the mid-1900s (Deven 183).
Most typical black and white photographs are “continuous tone” (as seen in the following example image), which means they are made of a full range of pure whites to deep blacks.
Because most printing process cannot reproduce a continuous tone, it must be mechanically re-created. This halftone technique can either be achieved by superimposing a halftone screen over the image before it is exposed or by creating a dot pattern when you print the image out from the computer to a transparent film.