Spirit duplicator

The faintly sweet aroma of pages fresh off the duplicator was a feature of school life in the spirit-duplicator era.

[5] The usual wax color was aniline purple (mauve), a cheap, moderately durable pigment that provided good contrast, but masters were also manufactured in red, green, blue, and black, as well as the hard-to-find orange, yellow, and brown.

Spirit duplicators had the useful ability to print multiple colors in a single pass, which made them popular with cartoonists.

The duplicating fluid typically consisted mostly of methanol or ethanol, both of which were inexpensive, readily available in quantity, evaporated quickly, and would not wrinkle the paper.

[6] In 1938,[7] a nonflammable solvent was invented by Johan Bjorksten to allow the possibility of using electrically driven machines without the concern of the flammability of pure methyl/ethyl alcohol.

The solvent mixture has a pleasant odor, reduced toxicity and gives at least as good copies as the duplication liquid before the addition of the trichlorofluoromethane.

Dittoed images gradually fade with exposure to ultraviolet light, limiting their usability for permanent labels and signage.