During the Industrial Revolution, oil colors were from inorganic pigments that are compounds of minerals, such as cobalt, cadmium, and manganese. These are the mineral colors, and they were developed for every hue on the color wheel. Their intense mass tones complemented earth colors on painters' palettes and replaced paints made from expensive semiprecious stones, fugitive colors, or highly toxic compounds. Impressionism would have been impossible without this full spectrum of pigments packaged for the first time as oil colors in tubes. While intense in their mass tones, mineral colors grey down when mixed with white.
Mineral colors are also the most opaque artists' colors.
Modern colors are very similar in masstone to the mineral colors. Modern colors are noted for their intense tinting strength and transparency. Most important, they do not grey down when mixed with white. Innovation in color chemistry throughout the 20th century has presented painters with another full spectrum of colors of modern organic pigments. These pigments are called organic because they are made from chemical compounds with a central carbon atom.