Alois Senefelder of Munich discovered the basic principle of Lithography, priting on stone, around 1798. Working with a highly porous stone, Senefelder sketched his design with a greasy substance, which was absorbed by the stone. He then wetted the entire surface with a mixture of gum Arabic and water (fountain solution). Only the stone areas absorbed the solution; the design area repelled it. Rolling on an ink made of soap, wax, oil and lampblack, this greasy substance coated the design but did not spread over the moist blank area. A clean impression of the design was made when a sheet of paper was pressed against the surface of the stone.
Artists soon used this new process to make reproductions of the works of old masters and, in time, recognized it as a valuable medium for their own original works. Lithography received its biggest boost during the mid 1900’s when new recognition and popularity encouraged printers to find more practical and faster methods of printing illustrations.
The first steam litho press was invented in France in 1850 and introduced in the U.S. by R. Hoe in 1868. Lithographic stones were used for the image and a blanket-covered cylinder received the image from the plate and transformed it to the substrate. Direct rotary presses for lithography using zinc and aluminum metal plates were introduced in the 1890’s. The first offset press was developed in 1906 by Ira A. Rubel (a paper manufacturer) by accident. An impression was unintentionally printed from a press cylinder directly onto the rubber blanket of the impression cylinder. Immediately afterward, when a sheet of paper was run through the press, a sharp image was printed on it from the impression which had been offset on the rubber blanket. A. F. Harris had noticed a similar effect. He then developed an offset press for the Harris Automatic Press Company in the same year, 1906.
The offset process came to be the most popular form of printing during the 1950’s as plates, inks, paper, etc. improved. By the late 1950’s, offset printing dominated all other printing pro cesses because it provided sharp clean images. While the offset printing process gave sharper, cleaner reproductions over letterpress, it was also less expensive in comparison to gravure. Today, the majority of printing (over 50%), in cluding newspapers, is done by the offset process.