List of duplicating processes - Definition and Overview

This is a partial list of duplicating processes used in business and government from the Industrial Revolution forward. Some are mechanical and some are chemical. There is naturally some overlap with printing processes and photographic processes, but the challenge of precisely duplicating business letters, forms, contracts, and other paperwork prompted some unique solutions as well. There were many short-lived inventions along the way.

Duplicating processes

Within each type, the methods are arranged in very rough chronological order.

• Methods of copying handwritten letters
  • Manifold stylographic writer, using early "carbonic paper"
  • Letter copying book process

• Printing/Applied ink methods
  • Printing press
  • Gelatin methods (also indirect method)
    • Hectograph
    • Collography, autocopyist
    • Chromograph, Copygraph, Polygraph
  • Flexography
  • Spirit duplicator (also ditto machine)

• Lithographic processes
  • Transfer lithography
  • Anastatic lithography
  • Autographic process
  • Offset lithography
  • Photolithography

• Stencil-based copying methods
  • Papyrography
  • Electric pen, invented by Thomas Edison
  • Trypograph (also file plate process)
  • Cyclostyle, Neostyle

• Stencil-based machines
  • Mimeograph
  • Roneo

• Typewriter-based copying methods
  • Carbon paper
  • Blueprint typewriter ribbon
  • Carbonless paper

• Photographic processes:
  • Reflex copying process (also reflectography, reflexion copying)
    • Breyertype, Playertype, Manul Process, Typon Process, Dexigraph, Linagraph
  • Daguerreotype
  • Salt print
  • Calotype
  • Cyanotype
  • Photostat
  • Airgraph (also V-mail)
  • Xerography
  • Kodagraph autopositive paper
  • Kodagraph repro-negative paper
  • Diffusion transfer
    • Verifax, Copyproof
    • Photomechanical transfer (also PMT')
  • Duostat, duoprint
  • Retroflex
  • Dual spectrum process

• Chemical processes
  • Aniline process
  • Blueprint process
  • Diazotype (also whiteprint, ammonia print, or gas print)

• Heat-sensitivity methods
  • Thermofax (also thermography)
  • Eichner drycopy process
  • Adherography

• Electrostatic methods
  • Electrofax