Next to the non-colors, raw umber and burnt umber are two of the most versatile and utilized colors in the decorative painter’s palette. In addition to the specific uses described below, both of these colors make a wonderful grey tonality when mixed with ultramarine blue and white.
RU – raw umber
Origins: Minerals from dark soil. Comes primarily from France, Italy and Germany.
Color: Each country region has different hue varying from warm-ish brown to green-ish brown, but always a medium dark in general.
Opacity: Average opacity often the more green-ish tend to be more transparent (based on my personal experience – perhaps not a scientific fact). In general, most are on the cool side, a grayish, green brown.
Uses: One of the main tonalities for patina or aged look. Many woodgrain techniques use raw umber a primary tonality. Some specific woodgrain examples are: English walnut, oak, grey Hungarian walnut, grey bird’s eye. Used in faux marble techniques mostly as a tertiary color — so bring down the intensity of a stronger color.
BU – burnt umber
Color: Burnt umber is made by burning raw umber in an oven at a high degree. An oxidation happens which turns raw umber to a reddish brown.
Opacity: semi-opaque to transparent (varies on the hue of RU)
Uses: This dark, reddish brown is used prevalently when woodgraining warm woods such as walnut, cherry, mahogany, rosewood, red oak, and burl. Used in faux marble techniques when mixed with other red tonalities. Some examples are cloudy marbles (such as rouge royal, cerfontaine, Saint Remy, and languedoc), verronese red, and yellow sienna.
This is an example of Saint Remy marble.