Definitions for "Cyanotype"
A photographic picture obtained by the use of a cyanide.
Developed by Sir John Hirschel (1842) and improved by Pellet in 1871, this technique creates a photographic image consisting of blue lines on a white background (or vice-versa). A forerunner of the modern blueprint process.
Cyanotypes are produced by placing a negative, plant speciman, or drawing on asheetof paper treated with iron salt and potassium ferricyanide. When the sheet is placed in direct sunlight, an impression will form that eventually turns bright blue (cyan) where it has been exposed to light and white where the sunlight was blocked. Although the process was first invented in 1841, most cyanotypes were produced from the late 1880s to 1920. One common use was for architectural drawings in blueprints.