Making COLORFUL Black
Mixing a Colorful Black - a colorful black is preferable to using pure black from a tube.
The more common way of creating a colorful black is by mixing ULTRAMARINE BLUE with an EARTH color. A different mixture that gives an even richer, deeper black is done by mixing equal parts of PRUSSIAN BLUE, ALIZARIN CRIMSON, and an EARTH color (BURNT SIENNA, but BURNT UMBER, RAW SIENNA, AND RAW UMBER work as well).
When this Colorful Black is added to white you get wonderful grays. Varying the amount of white added to these mixes creates several values of gray. If these grays are too blue, simply add a little more of the earth color to the original mixture, which will make the grays look more gray.
Use a Colorful Black to darken other colors Mixing small amounts of this colorful black into your colors will darken them without 'killing' the color like regular black would do.