Editing Cyanotype (section)

{{short description|Photographic printing process that produces a blue print}}
[[File:Anna Atkins algae cyanotype.jpg|right|thumb|A cyanotype of algae by 19th century botanist [[Anna Atkins]]]]
[[File:John Frederick William Herschel - Lady with a harp 1842.jpg|thumb|Sir John Herschel (1842) Experimental cyanotype of an unidentified engraving of a lady with a harp, Museum of the History of Science]]
[[File:Joy Oil gas station blueprints.jpg|right|thumb|Architectural drawing [[blueprint]], Canada, 1936]]
[[File:Cyanotype postcard, Racine, Wis., ca. 1910, front.jpg|thumb|Cyanotype postcard, Racine, Wis., c. 1910]]
The '''cyanotype''' (from {{langx|grc|κυάνεος}}, {{lang|grc-Latn|kyáneos}} {{gloss|dark blue}} and {{lang|grc|τύπος}}, {{lang|grc-Latn|týpos}} {{gloss|mark, impression, type}}) is a slow-reacting,  photographic printing formulation sensitive to a limited near-[[ultraviolet]] and [[blue light spectrum]], the range 300&nbsp;nm to 400&nbsp;nm known as UVA radiation.<ref name=":11" /> It produces a monochrome, blue-coloured print on a range of supports, and is often used for art and [[reprography]] in the form of [[blueprint]]s. For any purpose, the process usually uses two chemicals - [[Ammonium ferric citrate|ferric ammonium citrate]] or [[ferric ammonium oxalate]], and [[potassium ferricyanide]], and only water to develop and fix. Announced in 1842, it is still in use.