palettes | R Documentation |
Five color palettes each containing at least 22 different, distinguishable colors.
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)
n |
An integer; the number of colors desired. |
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.
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.
Kevin R. Coombes <krc@silicovore.com>
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.
createPalette
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)
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