Rublev Colours Cobalt Yellow (commonly called aureolin) is a potassium cobalt nitrite. The compound was discovered in 1831 but not introduced as a pigment until after 1851. It is an intense yellow that has high tinting strength and low opacity, popular as a watercolor. In watercolors, cobalt yellow is a transparent, lightly staining, intense yellow.
| Color Information | |
| Single Pigment: | Cobalt Yellow (Aureolin) |
| Binder: | Gum Arabic |
| Color Information | |
| Color: | Yellow |
| Color Index: | Pigment Yellow 40 (77357) |
| Chemical Name: | Hydrated Tripotassium Hexanitrocobalt(II) |
| Chemical Formula: | K3(Co(NO2)6).nH2O |
| CAS: | 13782-01-9 |
| Properties | |
| ASTM Lightfastness: | II |
| Opacity: | Transparent |
| Tinting Strength: | High |
| Staining: | Low |
| Granulating: | Low |
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NotesNote: Some separation of pigment and medium may occur in Rublev Colours Watercolors and is a natural process when no stabilizers are added to paint to prevent this from occurring.