When deepened, orange – unlike red and yellow – becomes brighter instead of darker. Few colorants produce pure orange. During the Middle Ages, orange mineral provided a rich, opaque pigment for easel painting and illuminated manuscripts.
Near the end of the 18th century, the emerging commercial paint industry developed synthetic iron oxides, “Mars Colors,” which made more predictable colors than natural earth pigments. Used for color consistency and opacity, Mars colors range from orange to dark red/purple.
Today, painters have several orange options. Painters like Wolf Kahn reach for Gamblin Transparent Orange, a warm color unique to the Gamblin palette.
Orange is the color of safety: orange life vests are easily seen on dark and stormy seas. Always a warm advancing color, orange is the forerunner of the sun.
During the Middle Ages, orange mineral, also called minium, provided a rich and opaque pigment that was used in easel painting and illuminated manuscripts. It was made by prolonged heating of white lead over an open fire. Noticeably toxic, Chinese bookmakers painted the edges of paper with orange mineral to save their books from silverfish. Orpiment, an extremely poisonous sulfide of arsenic, was mined as a yellow to reddish-yellow pigment. Its noxious sulfur fumes and highly reactive properties made orpiment a color of last choice. Realgar, another poisonous pigment found in the earth, made a better orange, but it was incompatible with lead or copper-based pigments.
Cadmium Orange was the first true orange. It is a pure hue with excellent opacity and low toxicity compared to its predecessors. Around 1820, yellow cadmium sulfide was discovered as an impurity in the processing of zinc ores. The name cadmium is derived from cadmia fornacum, a type of furnace used to smelt zinc. In experiments, chemists used hydrogen sulfide to precipitate the yellow colorant from solutions of cadmium salts. By 1880, they further discovered by gradually increasing the amount of selenium, they could produce deeper shades of cadmium orange and all shades of cadmium red.
