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Hectography

Printing process that involves transfer of an original

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Through Printing, Nail (anatomy) and World War II

Process

The special aniline dyes for making the master image came in the form of ink or in pens, pencils, carbon paper, and typewriter ribbon. Hectograph pencils and pens are sometimes still available. Various other inks have been found usable to varying degrees in the process; master sheets for spirit duplicators have also been pressed into service. Unlike a spirit duplicator master, a hectograph master is not a mirror image. Thus, when using a spirit duplicator master with a hectograph, one writes on the back of the purple sheet, using it like carbon paper to produce an image on the white sheet, rather than writing on the front of the white sheet to produce a mirror image on its back.

The master is placed on the gelatin and spirits applied to transfer the ink from the master to the gelatin. After transfer of the image to the inked gelatin surface, copies are made by pressing paper against it.

When a pad ceased to be useful, the gelatin could be soaked with spirits, the ink sponged away, and the pad left clean for the next master.

Storage

A grey-colored, thick, absorbent paper pad was supplied to cover the gelatin surface for storage. This also removed ink from the surface, but it took many hours to do so. Care needed to be taken that the gelatin surface was kept clean, and not damaged (e.g. by fingernails) during duplicating.

Although the name hectograph implies production of 100 copies, in reality the gelatin process produced print runs of somewhere between 20 and 80 copies, depending upon the skill of the user and the quality of the original. At least eight different colors of hectographic ink were available at one time, but purple was the most popular because of its density and contrast.

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