The Duplication of Office Material: Duplicating Processes

Hectography. There are two types of this process available, one producing a copy from gelatine or clay substance by the aid of violet dye or the method commonly known as the spirit process. Using rotary machines, hand or electric, the master is typed, drawn or impressed by the use of a hectographic carbon and a strongly sized highly glazed paper. The copy paper fed into the machine is slightly moistened by a special fluid which, in effect, softens a thin layer of the carbon deposit and transfers it from the master to the paper. The number of copies available by this method is limited by the thickness of the carbon deposit on the master but special masters are available allowing runs up to 500 copies. When the carbon deposit has not been completely exhausted the master may be re‐run up to the limit of its capacity. The unique feature of this process is that it allows multi‐coloured runs to be made simultaneously. This is made possible by the use of carbons of different colours. A wide range of machines is available for this process some of which are designed for systems work and are able to print part or whole of the master sheet. A minor disadvantage of the process is that the print is fugitive to direct sunlight and the carbon deposit may stain if not handled carefully. Specially coated masters and carbon ribbon in roll form are available and with the new methods of erasing errors do much to minimise this disadvantage.