Plan9 is a 256-color palette that partitions the 24-bit RGB space into 4×4×4 subdivision, with 4 shades in each subcube. Compared to the WebSafe, the idea is to reduce the color resolution by dicing the color cube into fewer cells, and to use the extra space to increase the intensity resolution. This results in 16 gray shades (4 gray subcubes with 4 samples in each), 13 shades of each primary and secondary color (3 subcubes with 4 samples plus black) and a reasonable selection of colors covering the rest of the color cube. The advantage is better representation of continuous tones.

This palette was used in the Plan 9 Operating System, described at


var Plan9 = []color.Color{
	color.RGBA{0x00, 0x00, 0x00, 0xff},
	color.RGBA{0x00, 0x00, 0x44, 0xff},
	color.RGBA{0x00, 0x00, 0x88, 0xff},
	color.RGBA{0x00, 0x00, 0xcc, 0xff},
	color.RGBA{0x00, 0x44, 0x00, 0xff},
	color.RGBA{0x00, 0x44, 0x44, 0xff},
	color.RGBA{0x00, 0x44, 0x88, 0xff},
	color.RGBA{0x00, 0x44, 0xcc, 0xff},
	color.RGBA{0x00, 0x88, 0x00, 0xff},
	color.RGBA{0x00, 0x88, 0x44, 0xff},
	color.RGBA{0x00, 0x88, 0x88, 0xff},
	color.RGBA{0x00, 0x88, 0xcc, 0xff},
	color.RGBA{0x00, 0xcc, 0x00, 0xff},
	color.RGBA{0x00, 0xcc, 0x44, 0xff},
	color.RGBA{0x00, 0xcc, 0x88, 0xff},
	color.RGBA{0x00, 0xcc, 0xcc, 0xff},
	color.RGBA{0x00, 0xdd, 0xdd, 0xff},
	color.RGBA{0x11, 0x11, 0x11, 0xff},
	color.RGBA{0x00, 0x00, 0x55, 0xff},
	color.RGBA{0x00, 0x00, 0x99, 0xff},
	color.RGBA{0x00, 0x00, 0xdd, 0xff},
	color.RGBA{0x00, 0x55, 0x00, 0xff},
	color.RGBA{0x00, 0x55, 0x55, 0xff},
	color.RGBA{0x00, 0x4c, 0x99, 0xff},
	color.RGBA{0x00, 0x49, 0xdd, 0xff},
	color.RGBA{0x00, 0x99, 0x00, 0xff},
	color.RGBA{0x00, 0x99, 0x4c, 0xff},
	color.RGBA{0x00, 0x99, 0x99, 0xff},
	color.RGBA{0x00, 0x93, 0xdd, 0xff},
	color.RGBA{0x00, 0xdd, 0x00, 0xff},
	color.RGBA{0x00, 0xdd, 0x49, 0xff},
	color.RGBA{0x00, 0xdd, 0x93, 0xff},
	color.RGBA{0x00, 0xee, 0x9e, 0xff},
	color.RGBA{0x00, 0xee, 0xee, 0xff},
	color.RGBA{0x22, 0x22, 0x22, 0xff},
	color.RGBA{0x00, 0x00, 0x66, 0xff},
	color.RGBA{0x00, 0x00, 0xaa, 0xff},
	color.RGBA{0x00, 0x00, 0xee, 0xff},
	color.RGBA{0x00, 0x66, 0x00, 0xff},
	color.RGBA{0x00, 0x66, 0x66, 0xff},
	color.RGBA{0x00, 0x55, 0xaa, 0xff},
	color.RGBA{0x00, 0x4f, 0xee, 0xff},
	color.RGBA{0x00, 0xaa, 0x00, 0xff},
	color.RGBA{0x00, 0xaa, 0x55, 0xff},
	color.RGBA{0x00, 0xaa, 0xaa, 0xff},
	color.RGBA{0x00, 0x9e, 0xee, 0xff},
	color.RGBA{0x00, 0xee, 0x00, 0xff},
	color.RGBA{0x00, 0xee, 0x4f, 0xff},
	color.RGBA{0x00, 0xff, 0x55, 0xff},
	color.RGBA{0x00, 0xff, 0xaa, 0xff},
	color.RGBA{0x00, 0xff, 0xff, 0xff},
	color.RGBA{0x33, 0x33, 0x33, 0xff},
	color.RGBA{0x00, 0x00, 0x77, 0xff},
	color.RGBA{0x00, 0x00, 0xbb, 0xff},
	color.RGBA{0x00, 0x00, 0xff, 0xff},
	color.RGBA{0x00, 0x77, 0x00, 0xff},
	color.RGBA{0x00, 0x77, 0x77, 0xff},
	color.RGBA{0x00, 0x5d, 0xbb, 0xff},
	color.RGBA{0x00, 0x55, 0xff, 0xff},
	color.RGBA{0x00, 0xbb, 0x00, 0xff},
	color.RGBA{0x00, 0xbb, 0x5d, 0xff},
	color.RGBA{0x00, 0xbb, 0xbb, 0xff},
	color.RGBA{0x00, 0xaa, 0xff, 0xff},
	color.RGBA{0x00, 0xff, 0x00, 0xff},
	color.RGBA{0x44, 0x00, 0x44, 0xff},
	color.RGBA{0x44, 0x00, 0x88, 0xff},
	color.RGBA{0x44, 0x00, 0xcc, 0xff},
	color.RGBA{0x44, 0x44, 0x00, 0xff},
	color.RGBA{0x44, 0x44, 0x44, 0xff},
	color.RGBA{0x44, 0x44, 0x88, 0xff},
	color.RGBA{0x44, 0x44, 0xcc, 0xff},
	color.RGBA{0x44, 0x88, 0x00, 0xff},
	color.RGBA{0x44, 0x88, 0x44, 0xff},
	color.RGBA{0x44, 0x88, 0x88, 0xff},
	color.RGBA{0x44, 0x88, 0xcc, 0xff},
	color.RGBA{0x44, 0xcc, 0x00, 0xff},
	color.RGBA{0x44, 0xcc, 0x44, 0xff},
	color.RGBA{0x44, 0xcc, 0x88, 0xff},
	color.RGBA{0x44, 0xcc, 0xcc, 0xff},
	color.RGBA{0x44, 0x00, 0x00, 0xff},
	color.RGBA{0x55, 0x00, 0x00, 0xff},
	color.RGBA{0x55, 0x00, 0x55, 0xff},
	color.RGBA{0x4c, 0x00, 0x99, 0xff},
	color.RGBA{0x49, 0x00, 0xdd, 0xff},
	color.RGBA{0x55, 0x55, 0x00, 0xff},
	color.RGBA{0x55, 0x55, 0x55, 0xff},
	color.RGBA{0x4c, 0x4c, 0x99, 0xff},
	color.RGBA{0x49, 0x49, 0xdd, 0xff},
	color.RGBA{0x4c, 0x99, 0x00, 0xff},
	color.RGBA{0x4c, 0x99, 0x4c, 0xff},
	color.RGBA{0x4c, 0x99, 0x99, 0xff},
	color.RGBA{0x49, 0x93, 0xdd, 0xff},
	color.RGBA{0x49, 0xdd, 0x00, 0xff},
	color.RGBA{0x49, 0xdd, 0x49, 0xff},
	color.RGBA{0x49, 0xdd, 0x93, 0xff},
	color.RGBA{0x49, 0xdd, 0xdd, 0xff},
	color.RGBA{0x4f, 0xee, 0xee, 0xff},
	color.RGBA{0x66, 0x00, 0x00, 0xff},
	color.RGBA{0x66, 0x00, 0x66, 0xff},
	color.RGBA{0x55, 0x00, 0xaa, 0xff},
	color.RGBA{0x4f, 0x00, 0xee, 0xff},
	color.RGBA{0x66, 0x66, 0x00, 0xff},
	color.RGBA{0x66, 0x66, 0x66, 0xff},
	color.RGBA{0x55, 0x55, 0xaa, 0xff},
	color.RGBA{0x4f, 0x4f, 0xee, 0xff},
	color.RGBA{0x55, 0xaa, 0x00, 0xff},
	color.RGBA{0x55, 0xaa, 0x55, 0xff},
	color.RGBA{0x55, 0xaa, 0xaa, 0xff},
	color.RGBA{0x4f, 0x9e, 0xee, 0xff},
	color.RGBA{0x4f, 0xee, 0x00, 0xff},
	color.RGBA{0x4f, 0xee, 0x4f, 0xff},
	color.RGBA{0x4f, 0xee, 0x9e, 0xff},
	color.RGBA{0x55, 0xff, 0xaa, 0xff},
	color.RGBA{0x55, 0xff, 0xff, 0xff},
	color.RGBA{0x77, 0x00, 0x00, 0xff},
	color.RGBA{0x77, 0x00, 0x77, 0xff},
	color.RGBA{0x5d, 0x00, 0xbb, 0xff},
	color.RGBA{0x55, 0x00, 0xff, 0xff},
	color.RGBA{0x77, 0x77, 0x00, 0xff},
	color.RGBA{0x77, 0x77, 0x77, 0xff},
	color.RGBA{0x5d, 0x5d, 0xbb, 0xff},
	color.RGBA{0x55, 0x55, 0xff, 0xff},
	color.RGBA{0x5d, 0xbb, 0x00, 0xff},
	color.RGBA{0x5d, 0xbb, 0x5d, 0xff},
	color.RGBA{0x5d, 0xbb, 0xbb, 0xff},
	color.RGBA{0x55, 0xaa, 0xff, 0xff},
	color.RGBA{0x55, 0xff, 0x00, 0xff},
	color.RGBA{0x55, 0xff, 0x55, 0xff},
	color.RGBA{0x88, 0x00, 0x88, 0xff},
	color.RGBA{0x88, 0x00, 0xcc, 0xff},
	color.RGBA{0x88, 0x44, 0x00, 0xff},
	color.RGBA{0x88, 0x44, 0x44, 0xff},
	color.RGBA{0x88, 0x44, 0x88, 0xff},
	color.RGBA{0x88, 0x44, 0xcc, 0xff},
	color.RGBA{0x88, 0x88, 0x00, 0xff},
	color.RGBA{0x88, 0x88, 0x44, 0xff},
	color.RGBA{0x88, 0x88, 0x88, 0xff},
	color.RGBA{0x88, 0x88, 0xcc, 0xff},
	color.RGBA{0x88, 0xcc, 0x00, 0xff},
	color.RGBA{0x88, 0xcc, 0x44, 0xff},
	color.RGBA{0x88, 0xcc, 0x88, 0xff},
	color.RGBA{0x88, 0xcc, 0xcc, 0xff},
	color.RGBA{0x88, 0x00, 0x00, 0xff},
	color.RGBA{0x88, 0x00, 0x44, 0xff},
	color.RGBA{0x99, 0x00, 0x4c, 0xff},
	color.RGBA{0x99, 0x00, 0x99, 0xff},
	color.RGBA{0x93, 0x00, 0xdd, 0xff},
	color.RGBA{0x99, 0x4c, 0x00, 0xff},
	color.RGBA{0x99, 0x4c, 0x4c, 0xff},
	color.RGBA{0x99, 0x4c, 0x99, 0xff},
	color.RGBA{0x93, 0x49, 0xdd, 0xff},
	color.RGBA{0x99, 0x99, 0x00, 0xff},
	color.RGBA{0x99, 0x99, 0x4c, 0xff},
	color.RGBA{0x99, 0x99, 0x99, 0xff},
	color.RGBA{0x93, 0x93, 0xdd, 0xff},
	color.RGBA{0x93, 0xdd, 0x00, 0xff},
	color.RGBA{0x93, 0xdd, 0x49, 0xff},
	color.RGBA{0x93, 0xdd, 0x93, 0xff},
	color.RGBA{0x93, 0xdd, 0xdd, 0xff},
	color.RGBA{0x99, 0x00, 0x00, 0xff},
	color.RGBA{0xaa, 0x00, 0x00, 0xff},
	color.RGBA{0xaa, 0x00, 0x55, 0xff},
	color.RGBA{0xaa, 0x00, 0xaa, 0xff},
	color.RGBA{0x9e, 0x00, 0xee, 0xff},
	color.RGBA{0xaa, 0x55, 0x00, 0xff},
	color.RGBA{0xaa, 0x55, 0x55, 0xff},
	color.RGBA{0xaa, 0x55, 0xaa, 0xff},
	color.RGBA{0x9e, 0x4f, 0xee, 0xff},
	color.RGBA{0xaa, 0xaa, 0x00, 0xff},
	color.RGBA{0xaa, 0xaa, 0x55, 0xff},
	color.RGBA{0xaa, 0xaa, 0xaa, 0xff},
	color.RGBA{0x9e, 0x9e, 0xee, 0xff},
	color.RGBA{0x9e, 0xee, 0x00, 0xff},
	color.RGBA{0x9e, 0xee, 0x4f, 0xff},
	color.RGBA{0x9e, 0xee, 0x9e, 0xff},
	color.RGBA{0x9e, 0xee, 0xee, 0xff},
	color.RGBA{0xaa, 0xff, 0xff, 0xff},
	color.RGBA{0xbb, 0x00, 0x00, 0xff},
	color.RGBA{0xbb, 0x00, 0x5d, 0xff},
	color.RGBA{0xbb, 0x00, 0xbb, 0xff},
	color.RGBA{0xaa, 0x00, 0xff, 0xff},
	color.RGBA{0xbb, 0x5d, 0x00, 0xff},
	color.RGBA{0xbb, 0x5d, 0x5d, 0xff},
	color.RGBA{0xbb, 0x5d, 0xbb, 0xff},
	color.RGBA{0xaa, 0x55, 0xff, 0xff},
	color.RGBA{0xbb, 0xbb, 0x00, 0xff},
	color.RGBA{0xbb, 0xbb, 0x5d, 0xff},
	color.RGBA{0xbb, 0xbb, 0xbb, 0xff},
	color.RGBA{0xaa, 0xaa, 0xff, 0xff},
	color.RGBA{0xaa, 0xff, 0x00, 0xff},
	color.RGBA{0xaa, 0xff, 0x55, 0xff},
	color.RGBA{0xaa, 0xff, 0xaa, 0xff},
	color.RGBA{0xcc, 0x00, 0xcc, 0xff},
	color.RGBA{0xcc, 0x44, 0x00, 0xff},
	color.RGBA{0xcc, 0x44, 0x44, 0xff},
	color.RGBA{0xcc, 0x44, 0x88, 0xff},
	color.RGBA{0xcc, 0x44, 0xcc, 0xff},
	color.RGBA{0xcc, 0x88, 0x00, 0xff},
	color.RGBA{0xcc, 0x88, 0x44, 0xff},
	color.RGBA{0xcc, 0x88, 0x88, 0xff},
	color.RGBA{0xcc, 0x88, 0xcc, 0xff},
	color.RGBA{0xcc, 0xcc, 0x00, 0xff},
	color.RGBA{0xcc, 0xcc, 0x44, 0xff},
	color.RGBA{0xcc, 0xcc, 0x88, 0xff},
	color.RGBA{0xcc, 0xcc, 0xcc, 0xff},
	color.RGBA{0xcc, 0x00, 0x00, 0xff},
	color.RGBA{0xcc, 0x00, 0x44, 0xff},
	color.RGBA{0xcc, 0x00, 0x88, 0xff},
	color.RGBA{0xdd, 0x00, 0x93, 0xff},
	color.RGBA{0xdd, 0x00, 0xdd, 0xff},
	color.RGBA{0xdd, 0x49, 0x00, 0xff},
	color.RGBA{0xdd, 0x49, 0x49, 0xff},
	color.RGBA{0xdd, 0x49, 0x93, 0xff},
	color.RGBA{0xdd, 0x49, 0xdd, 0xff},
	color.RGBA{0xdd, 0x93, 0x00, 0xff},
	color.RGBA{0xdd, 0x93, 0x49, 0xff},
	color.RGBA{0xdd, 0x93, 0x93, 0xff},
	color.RGBA{0xdd, 0x93, 0xdd, 0xff},
	color.RGBA{0xdd, 0xdd, 0x00, 0xff},
	color.RGBA{0xdd, 0xdd, 0x49, 0xff},
	color.RGBA{0xdd, 0xdd, 0x93, 0xff},
	color.RGBA{0xdd, 0xdd, 0xdd, 0xff},
	color.RGBA{0xdd, 0x00, 0x00, 0xff},
	color.RGBA{0xdd, 0x00, 0x49, 0xff},
	color.RGBA{0xee, 0x00, 0x4f, 0xff},
	color.RGBA{0xee, 0x00, 0x9e, 0xff},
	color.RGBA{0xee, 0x00, 0xee, 0xff},
	color.RGBA{0xee, 0x4f, 0x00, 0xff},
	color.RGBA{0xee, 0x4f, 0x4f, 0xff},
	color.RGBA{0xee, 0x4f, 0x9e, 0xff},
	color.RGBA{0xee, 0x4f, 0xee, 0xff},
	color.RGBA{0xee, 0x9e, 0x00, 0xff},
	color.RGBA{0xee, 0x9e, 0x4f, 0xff},
	color.RGBA{0xee, 0x9e, 0x9e, 0xff},
	color.RGBA{0xee, 0x9e, 0xee, 0xff},
	color.RGBA{0xee, 0xee, 0x00, 0xff},
	color.RGBA{0xee, 0xee, 0x4f, 0xff},
	color.RGBA{0xee, 0xee, 0x9e, 0xff},
	color.RGBA{0xee, 0xee, 0xee, 0xff},
	color.RGBA{0xee, 0x00, 0x00, 0xff},
	color.RGBA{0xff, 0x00, 0x00, 0xff},
	color.RGBA{0xff, 0x00, 0x55, 0xff},
	color.RGBA{0xff, 0x00, 0xaa, 0xff},
	color.RGBA{0xff, 0x00, 0xff, 0xff},
	color.RGBA{0xff, 0x55, 0x00, 0xff},
	color.RGBA{0xff, 0x55, 0x55, 0xff},
	color.RGBA{0xff, 0x55, 0xaa, 0xff},
	color.RGBA{0xff, 0x55, 0xff, 0xff},
	color.RGBA{0xff, 0xaa, 0x00, 0xff},
	color.RGBA{0xff, 0xaa, 0x55, 0xff},
	color.RGBA{0xff, 0xaa, 0xaa, 0xff},
	color.RGBA{0xff, 0xaa, 0xff, 0xff},
	color.RGBA{0xff, 0xff, 0x00, 0xff},
	color.RGBA{0xff, 0xff, 0x55, 0xff},
	color.RGBA{0xff, 0xff, 0xaa, 0xff},
	color.RGBA{0xff, 0xff, 0xff, 0xff},