Michael Harding Cobalt Blue - Introduced at about the same time as Ultramarine, Cobalt Aluminate is a synthetic inorganic pigment. It is a more greenish-blue, with a heavier, more mineral appearance when seen as dry pigment. The hues formed from it are correspondingly heavier and more grey. But it has a certain shade that the less expensive ultramarine cannot quite match. The paint film when cured is quite soft.
| Color Index | PB28 |
| Drying Speed | Very Fast |
| Transparency | Semi-Transparent |
| Lightfastness | Excellent |
| Oil Content | Average |
| Tint Power | Average |
| Toxicity | Non-Toxic |
| ASTM D-4236 | ✓ |
| Prop 65 | ✓ |
![[no. 506] Cobalt Blue - M. Harding Oil - 40ml](http://www.raymar.com/cdn/shop/products/MH_Cobalt_Blue_40ml_{width}x.jpg?v=1636520618)
![[no. 506] Cobalt Blue - M. Harding Oil - 40ml](http://www.raymar.com/cdn/shop/products/506CobaltBlue_{width}x.jpg?v=1636520585)