PG18—Viridian
Pigment Type
inorganic
Chemical Name
chromium(III)-oxide dehydrate
Chemical Formula
Cr2O3 • 2 H2O or Cr2(OH3)
Properties
Viridian is the standard green and is stable, powerful, and cold with an emerald green undertone. It has a transparent hue, good tinting strength, a dark masstone that can be almost black at full strength, and a slow drying time in oil form. Viridian is commonly replaced by the darker, more saturated, and staining Phthalo Greens, but its properties make it a necessary part of the palette of an experienced landscape painter.
Permanence
Viridian has excellent permanence, except in high-temperature work, and is highly valued as a glazing color.
Toxicity
Viridian is slightly toxic.
History
Viridian’s name comes from the Latin viridis, meaning green. The process for manufacturing Viridian, or Transparent Oxide of Chromium, was patented by Guignet in Paris in 1859. However, it had actually been discovered by Pannetier and Binet in 1838. Viridian replaced Verdigris, which was reactive and unstable, and Emerald Green, which was a poisonous copper aceto-arsenite used as a rat poison in the sewers of Paris.
Alternate Names
Emerald Chromium Oxide, Emeraude Green, French Veronese Green, Guignet’s Green, Pannetier's Green, Permanent Green, Smaragd Green, Transparent Oxide of Chromium, Vert Emeraude. Casali's Green and Mittler's Green are varieties of Viridian. Viridian has historically been sold under the name Emerald Green, but they are currently considered to be and are marketed as two different pigments.
