Munsell Book of Color
Science History Institute/Gregory Tobias

Our eyes can tell us a great deal about our surroundings. Think about the differences in color of grass or plants during times of drought or the differences in soil color in various parts of the country. But your perception of colors is subjective: what you consider to be yellow-red may be someone else’s dark orange. The Munsell color system has provided scientists with a good standard of color for soil and plants since the 1930s and is still the U.S. Department of Agriculture’s official soil-research color system.

Developed by art professor Albert Munsell in the early 1900s, the charts attempt to classify colors numerically based on three categories in three-dimensional space: hue, value (lightness/darkness), and chroma (intensity of color). Munsell, who was interested in color theory, wanted to standardize color classification to avoid the variations of opinion that resulted from the subjective methods of his day.

The charts are easily transportable into the field. Trained users can quickly match the color of their sample, plant or soil, to the chart for an initial baseline. The charts, still used today in fields from criminal forensics to forestry, have provided a basis for even more specific color coding.