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
Orange (colour) and political activities, with the colour orange being associated with Protestantism similar to the Netherlands. In optics, orange is the colour seen by the eye when looking at light with a wavelength between approximately 585–620 nm. It has a hue of 30° in HSV colour space. In the traditional colour wheel used by painters, orange is the range of colours between red and yellow, and painters can obtain orange simply by mixing red and yellow in various proportions; however these colours are never as vivid as a pure orange pigment. In the RGB colour model (the system used to create