When i was in grade school i remember this copier that printed in purple ink and the secretary had to turn a handle to produce copies.
Old copy machine with purple ink.
The master for the ditto was only good for a limited number of copies as the solvent spirit dissolved.
Stencil duplication was a low cost printing method that worked by forcing ink through waxed paper stencils on to target paper.
Ditto machines made the purple copies that faded over time faster with exposure to light.
A ditto machine was a primitive photocopier that used a solvent like methylated spirits or ammonia to transfer ink from the master copy the template if you will onto other pieces of paper.
Ideally each ink color would have its own screen.
When the gelatin got too saturated with ink dad would liquidize it by heating it and re pour it into the pan les newcomer reports that the heyer hectograph co.
They have now been replaced by digital duplicators scanners laser printers and photocopiers but for many years they were the primary means of reproducing documents for limited run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.
Duplicating machines were the predecessors of modern document reproduction technology.
Sold a hectograph kit as late as 1974 tray gelatin a few sheets of purple inked paper and that thick cover.
I never knew to actual name of it.
I guess we changed those.
The ink came in tubes.
The mimeograph process should not be confused with the spirit duplicator process.
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.
Mimeographs along with spirit duplicators and hectographs were a common technology in printing small quantities as in office work classroom.
We just cleaned it out to change color.
The tray was only 1 4 deep.
Ditto machine purple print and that smell.
The stencil was thin rubber backed with paper and it was critical to get this on right while peeling the paper backing.
It didn t use a drum.
There were two cylinders with a silkscreen belt running on them.