Kalyan Banerjee

Litho History and Principle Invented in 1798 by the Bavarian Alois Senefelder, lithography literally means “writing on stone”.

The process was so named by H. Banks (1813) because

Senefelder used slabs of porous limestone as printing surfaces. On these he drew designs with greasy ink, and after applying a film of water to the surface of the stone, the inked designs were transferred to sheets of paper by means of pressure. This is the basic principle of lithography – the mutual antipathy (repulsion) of grease and water – a principle which has not changed since Senefelder’s day, though limestone has given way to sheets of flexible metal and other surfaces for use on modern offset presses. Manual engraving on stone was performed in 175 A.D. by the Chinese, and Senefelder’s first use of stone as a printing surface was not for the purpose of lithography – it was an attempt at relief etching! Senefelder was familiar with the process of etching on copper, and the oftrepeated statement that he accidentally discovered lithography by hastily writing a laundry list on stone is a fairly tale. The list was written on stone by Senefelder with stone ink (because of the momentary lack of paper and writing ink), but he etched the writing into relief with acid and took an impression therefrom by the letter press principle. There was nothing accidental about Senbefelder’s invention of lithography! It was the result of lengthy and arduous research, and a brief outline of his efforts will help a further explain the basic principles of lithography. Senefelder eventually found that by writing on a piece of litho stone with some black ink he had prepared from soap, beeswax, tallow, resin and lampblack, only repolishing of the stone would remove what he had written. He also found that repeated washing of the stone with water and turpentine removed the black ink, but that an almost invisible image of grease had meanwhile been absorbed by the surface of the stone. By keeping the stone dampened with water, he could reink the writing by rubbing more black ink on the almost invisible image, and thus bring it back as

good as new. By placing a sheet of paper face down on the inked stone and applying a roller to the back of the sheet, he found he could print as may copies as were needed from his original drawing on stone. Senefelder’s basic work established that the surface of the stone absorbed grease and remained grease-attraction when wetted with water and that the bare areas of the stone remained wettable by water. The printing and non - printing areas of all modern lithographic plates have maintained these characteristics, and though our methods of arriving at the final litho plate are many and

Senefelder’s original principles still

apply. Until the end of the nineteenth century most lithography was produced by drawing with grease crayon and ink on Solenhofen limestone. When the artist was finished with his work, the stone would be desensitized with acid gum arabic applied with a sponge and dried down. This helped prevent the greasy ink from adhering to the printing area during the rolling up operation with. The transfer of ink to paper was accomplished by a press resembling a laundry wringer, this transferring the ink to the paper by means of pressure. Re damping re inking of the stone were repeated for the length of the edition. This was the principle and procedure, employed by the stipple artist and chromolithographer, who hewed out niche in the field of color reproduction. Chromolithography

was

a

strictly

manual

operation,

involving

numerous

“colorplates” (stones) printed in different hues and tints. Senefelder himself laid the foundation (1800) chromolithography in eight or nine colors. Later artists used 20 or more color and created a craft which reigned supreme until the vent of the tricolor halftone process. The process of lithography, a slab of line stone four to six inches thick wasn’t exactly a convener printing surface.

Senefelder himself was aware of the and in 1801

conducted experiments with zinc plates as possible substitute for the heavy and unwieldy litho stone. But metal plates did not gain quick popularity, and the first use was for “hand transfer” purposes.

By pulling impressions from stone onto a special coated paper, it was possible to reapply these impressions to a clean gained metal plate and produce lithography printing surface. Any image that was drawn once on a stone could be repeatedly printed on many sheets of this “transfer” paper. These were carefully assembled on a template, face up onto a predetermined sheet layout. A clean and grained zinc or aluminum plate would be carefully laid face down on the assembled template of impressions, and the sandwich passed through a “pull-over press,” which applied enough pressure to transfer the ink images from the paper to the plate. The “hand transferred” as the lithographer handling this phase of the work was called, would lay the zinc plate face up on a table and proceed to dampen and remove the paper still adhering to the surface of the plate. At this point the plate resembled Senefelder’s stone surface in that grease image was absorbed by the surface of the metal. After desensitizing the nonprinting surface of the plate with a mixture of water, gum arabic, an acid and a bichromate or phosphate salt, the plate could be safely damped and inked up. After inspection and corrections, the plate was made ready for press. The fact that “hand transfer” plates had a grease image that was directly in contact with the metal made this surface a very durable one, especially when compared to the “photo” plates made about the turn of the century. The prototypes of our present photolith plates were unreliable and short-lived.