2

Colour

This chapter focuses on the colour used in risoprinting. Topics include the distinctive colour composition, the variety of the risograph’s ink palette and the technique behind colour separations; it also briefly shows how to create colour profiles for the risograph.

The risograph uses an emulsion ink, which consists of a mix of oil and water bases.1 Emulsion (lat. Ex and mulgēre, “milked”) is a process in which two unmixable substances are combined with an emulsifier; this produces a compound of two liquids that would normally not mix without any visible separation. Examples of emulsions include cosmetics, milk, mayonnaise or, as in this case, colour based on soybean oil.2

  1. RISO Kagaku Corp., US Patent 5,779,777A, 1996, https://www.google.com/patents/US5779777, last retrieved 25 September 2020.
  2. Carleton Ellis, Printing Inks: Their Chemistry and Technology (New York: Reinhold Publishing Corporation, 1940), 345.