Cyanotype is one of photography’s oldest processes. Sir John Herschel devised it in 1842, and it still gives the same deep Prussian blue. Paper coated with light-sensitive iron salts is exposed to UV light, then washed in plain water, and the image appears as the unexposed salts rinse away. This collection brings together cyanotypes by Craig Keenan, Maxine Gregson, Ewan Taylor and Kay Gasei, from mini prints to framed originals.