Michael Harding Raw Umber is one of the fundamental Earths used as an imprimitura pigment to draw out compositions as a ground, as many Rubens sketches prove. Depending on the degree of transparency it exhibits greenish undertones.
| Color Index | PBr6 |
| Drying Speed | Very Fast |
| Transparency | Semi-Transparent |
| Lightfastness | Excellent |
| Oil Content | Average |
| Tint Power | Average |
| Toxicity | Non-Toxic |
| ASTM D-4236 | ✓ |