Sunday, August 13, 2006

What I Learned About This Week


Lithography

Lithography was invented by Alois Senefelder in Bohemia in 1798, and it was the first new printing process since the invention of relief printing in the fifteenth century. In the early days of lithography, a smooth piece of limestone was used (hence the name "lithography"—"lithos" is the ancient Greek word for stone). After the oil-based image was put on the surface, acid burned the image onto the surface; gum arabic, a water soluble solution, was then applied, sticking only to the non-oily surface and sealing it. During printing, water adhered to the gum arabic surfaces and avoided the oily parts, while the oily ink used for printing did the opposite.

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