Prussian Blue

Produced by accident in 1704 when Colourman Johannes Diesbach was preparing what he thought was going to be a crimson lake pigment. The potash was contaminated with blood, and Diesbach produced a unique colourant that wasn’t like anything that had been produced before: a deep, nearly black blue. Prussian Blue. The first synthetic organic pigment. The colour is similar in both mass-tone and undertone to Phthalocyanine Blue (Winsor Blue), although not nearly its equal in tinting strength. Good transparency and clarity in undertone.

Alkali Ferriferrocyanide, PB27 A – Permanent (Fluctuating colour; fades in light, recovers in dark) ; ASTM I Series 1 Transparent Staining