palettes {Polychrome}

Polychrome Color Palettes

Description

Five color palettes each containing at least 22 different, distinguishable colors.

Usage

kelly.colors(n = 22)
glasbey.colors(n = 32)
green.armytage.colors(n = 26)
palette36.colors(n = 36)
alphabet.colors(n = 26)
light.colors(n = 24)
dark.colors(n = 24)
sky.colors(n = 24)

Arguments

n

An integer; the number of colors desired.

Details

Kenneth Kelly, a physicist who worked at the United States National Bureau of Standards and chaired the Inter-Society Color Council Subcommittee on Color Names, made one of the earliest attempts to find a set of colors that could be easily distinguished when used in graphs. The kelly.colors function produces a palette from the 22 colors that he produced, using his color names. These are ordered so that the optimal contrast for any palette with fewer than 22 colors can be selected from the top of his list.

Glasbey and colleagues used a sequential search algorithm in CIE LAB color space to create a palette of 32 well-separated colors.

Paul Green-Armytage described a study growing out of a workshop held by the Colour Society of Australia in 2007 to test whether an alphabet composed of 26 distinguishable colors would serve in place of the usual symbols of the English alphabet. Each color is given a name starting with a different letter of the alphabet, which was found to make it easier for people to learn the association and read sentences written in color. The green.armytage.colors function produces palettes from his final color set, arranged in "alphabetical" order rather than by maximum contrast.

Carter and Carter followed Kelly's article with a study that showed that "perceptual distinguishability" of colors was related to their Euclidean distance in the L*u*v* color space coordinates, as defined by the International Commisision on Illumination (CIE). They also found that distinguishability falls off rapidly when the distance is less than about 40 L*u*v* units. We implemented a palette-construction algorithm based on this idea. The palette36.colors function returns palettes from the resulting list of 36 colors, with names assigned using the ISCC-NSB standard.

The alphabet.colors function uses the first 26 colors from "palette36" but assigns them names beginning with different letters of the English alphabet and reorders them accordingly.

The light.colors and dark.colors functions use one of the two 24-color palettes (Light24 or Dark24) customized to limit the luminance range.

The sky.colors function uses the 24-color palette constructed by Coombes et al. to match as closely as possibkle te palette used by the standard software useed by cytogeneticists to display the results of spectral karyotyping.

Value

Each function returns a character vector of hexadecimal color values (such as "#EA9399"). Each color is assigned a name (such as "Strong_Pink"). The default value is the maximum number of colors available from the individual palette.

Author(s)

Kevin R. Coombes <[e-mail]>

References

Kelly KL. Twenty-Two Colors of Maximum Contrast. Color Eng., 1965; 3:26–7.

Green-Armytage, P. A Colour Alphabet and the Limits of Colour Coding. Colour: Design and Creativity, 2010; 10:1–23.

Carter RC, Carter EC. High-contrast sets of colors. Applied Optics, 1982; 21(16):2936–9.

Coombes KR, Brock G, Abrams ZB, Abruzzo LV. Polychrome: Creating and Assessing Qualitative Palettes with Many Colors. Journal of Statistical Software. 2019; 90(1):1–23.

See Also

createPalette

Examples

palette36.colors(5)
kelly.colors(5)
alphabet.colors(7)
glasbey.colors(9)
green.armytage.colors(3)
light.colors(6)
dark.colors(11)
sky.colors(4)