The Forgotten Pigment: Verditer's History and Lack of Lightfastness

Verditer is a synthetic pigment that was widely used in the 19th and early 20th centuries as a substitute for Prussian blue. It was made by reacting ferric ammonium sulfate with sodium salicylate, and it has a similar color to Prussian blue but is less lightfast and more susceptible to fading. Verditer was used in a variety of applications, including painting, printing, and textiles, but it has largely been replaced by more lightfast pigments in modern times.