Copying pencil

The lead is fabricated by adding a dry water-soluble permanent dye to powdered graphite—used in standard graphite pencils—before binding the mixture with clay.

The water-soluble dye in the writing would be transferred in its mirror image to the tissue paper, which could then be read in verso by holding it up to a light source.

Since the aniline dye was poisonous to humans, many injuries and illness related to copying pencils were reported in the medical literature, especially in the late-19th and early-20th centuries.

The copying pencil served as a convenient substitute for the fountain-pen: it could be carried on one's person without need for ink or fear of leaks.

In countries like India and the Soviet Union,[4] they were commonly used for writing addresses on registered mail parcels, which were required by law to be wrapped in cloth—usually plain white or unbleached calico—and secured with twine and sealing wax.

For writing an address on cloth, a moistened copying pencil was preferred to a pen, whose nib could easily get caught in the weave.