Widely used throughout the 20th Century by schools, churches, fan clubs, and other small organizations, Spirit Duplicators or “Ditto” machines allowed small runs of documents to be copied cheaply and quickly. Often conflated with mimeographs, they were in fact a distinct technology, used a master sheet printed with dye-bearing wax instead of liquid ink. Paper passing through the machine was wetted with a solvent and pressed against the master sheet, causing some of the dyed wax to dissolve and transfer onto the paper.