Old Copy Machine With Blue Ink

Ideally each ink color would have its own screen.

Old copy machine with blue ink.

Ditto machines made the purple copies that faded over time faster with exposure to light. The stencil was thin rubber backed with paper and it was critical to get this on right while peeling the paper backing. The master for the ditto was only good for a limited number of copies as the solvent spirit dissolved the surface of the ink on the master allowing it to be transferred to the special paper. It didn t use a drum.

The ink came in tubes. There were two cylinders with a silkscreen belt running on them. They have now been replaced by digital duplicators scanners laser printers and photocopiers but for many years they were the primary means of reproducing documents for limited run distribution the duplicator was pioneered by thomas edison and david gestetner with gestetner dominating the market up until. It did not always produce high quality copies and the ink could be messy.

I believe that you are referring to a mimeograph machine. The blue process while a number of technologies that used photosensitive paper to copy documents were invented beginning in 1842 the first of these technologies that was commercially important was the blue process while the blue process was well established in europe by the early 1870s it was not introduced in the us until 1877. However the cost of early photocopiers was quite high. The stencil duplicator or mimeograph machine is a low cost duplicating machine that works by forcing ink through a stencil onto paper.

We just cleaned it out to change color. A mechanical duplicator that produced copies by pressing ink often by manually turning a handle onto paper through openings cut in a stencil. The mimeograph process should not be confused with the spirit duplicator process. I guess we changed those.

Mimeographs along with spirit duplicators and hectographs were a common technology in printing small quantities as in office work classroom materials and church bulletins. In the late 1960s. Both pieces of paper are stained with purple ink because they went through a machine invented in 1923 called a ditto machine or spirit duplicator.