anastatic printing

A method of zincography invented by Wood in 1841, designed to reproduce drawings, engravings, printed matter, ., whether recent or old. If, for instance, it be sought to obtain the fac simile of an old newspaper, the paper is first wetted with dilute phosphoric acid, and then placed between sheets of blotting paper to remove the superfluous moisture. It is then found that the acid has corroded the blanks, but has not affected the printed letters. The sheet is next placed in contact with a plate, and pre ure applied, which makes a fac - simile of the letters in reverse order on the plate. Gum is next applied, and more ink, then a little acid, and finally again ink, when the printing stands out as clear and distinct as in the original.