Duplicating machines
They have now been replaced by digital duplicators, scanners, laser printers, and photocopiers, but for many years they were the primary means of reproducing documents for limited-run distribution.
[1] This second phase brought to mass markets technologies like the small electric motors and the products of industrial chemistry without which the duplicating machines would not have been economical.
They were often used in schools, churches, and small organizations, where revolutionarily economical copying was in demand for the production of newsletters and worksheets.
[citation needed] John Isaac Hawkins and Charles Willson Peale patented a polygraph in the US in 1803, and beginning in 1804 Thomas Jefferson collaborated with them in working on improvements in the machine.
Letter copying presses were used by the early 1780s by the likes of Benjamin Franklin, George Washington, Henry Cavendish, and Thomas Jefferson.
The cores of copying pencils, which appear to have been introduced in the 1870s, were made from a mixture of graphite, clay, and aniline dye.
The Process Letter Machine Co. of Muncie, Indiana, offered the New Rotary Copying Press, a loose-leaf copier, in 1902.
[further explanation needed] While good-quality, reasonably rapid copies from a hectograph require fairly specific materials (Aniline dye is the most effective), passable copies can be produced from a bewildering array of improvised materials on makeshift equipment.
This meant that improvised hectography assumed the role of reproducing nearly every sort of censored material from subversive literature to pornography.
[further explanation needed] The mimeograph invented by Albert Blake Dick in 1884 used heavy waxed-paper "stencils" that a pen or a typewriter could cut through.
The pressure of writing or typing on the top sheet transferred colored wax to its back side, producing a mirror image of the desired marks.
Unlike mimeo, ditto had the useful ability to print multiple colors in a single pass, which made it popular with cartoonists.
Notoriously, images would gradually fade with exposure to light[citation needed], limiting their usability for permanent labels and signage.
Copies made by spirit duplicators now pose a serious challenge to archivists responsible for document textual and artistic preservation.
Overall print quality of spirit duplicators was frequently poor, though a capable operator could overcome this with careful adjustment of feed rate, pressure, and solvent volume.
[citation needed] During their heyday, tabletop duplicators of both sorts were the inexpensive and convenient alternatives to conventional typesetting and offset or letterpress printing.
[citation needed] The machines owed most of their popularity to this relative ease of use, and in some cases, to their lack of a requirement for an external power source.
Also, mimeographed images were as durable as the paper they were printed on, and didn't bleach to illegibility if exposed to sunlight, the way that spirit duplicator pages did.
Duplicators were manufactured by Heidelberg (T-offset), American Type Founders (Chief and Davidson lines), A.B.
Other manufacturers have adapted the technology including: Like the mimeo machine, digital duplicators have a stencil (called a master), ink, and drum—but the process is all automated.
