spirit process

n.A technique to make multiple copies of a document from a master.

Notes

Spirit process and ditto are often used as synonyms. The master is a heavy piece of paper, which is placed in front of a sheet with a coating of wax and carbon. Writing or typing on the front of the master transfers the wax to the back of the master. During printing, alcohol is used to dissolve a thin layer of the wax on the back of the master, which is then transferred to a sheet of paper.