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
Shades of green color standard is displayed at right. It is the color called green, low green or medium green in many of the older eight-bit computer palettes. Another name for this color is "green W3C". This is the X11/HTML color "dark green". The color defined as "green" in the CMYK color system used in printing, also known as "pigment green", is the tone of green that is achieved by mixing process (printer's) cyan and process (printer's) yellow in equal proportions. It is displayed at right. The purpose of the CMYK color system is to provide the maximum possible gamut of color reproducible