Tertiary color if they exist at all, though indigo and scarlet are standard for blue–violet and red–vermilion. In another sense, a tertiary color is obtained by mixing secondary-colored pigments. These three colors are russet (orange–purple), slate (purple–green), and citron (green–orange), with the corresponding three quaternary colors plum (russet–slate), sage (slate–citron), buff (citron–russet) (with olive sometimes used for either slate or citron). Beyond that are shades of grey (blue grey and brown greys), which approach but never quite reach black. The RYB color terminology outlined above and in the color samples shown below is ultimately derived from the 1835 book "Chromatography", an analysis
Comparison of color models in computer graphics primary colors. The complement of a hue is the hue that is opposite it (180 degrees) on the color wheel. Using additive colors, mixing a hue and its complement in equal amounts produces white. The following discussion uses an illustration involving three projectors pointing to the same spot on a screen. Each projector is capable of generating one hue. The "intensities" of each projector are "matched" and can be equally adjusted from zero to full. (Note: "Intensity" is used here in the same sense as the RGB color model. The subject of matching, or "gamma correction", is beyond the level