- List of software palettes
:::"For a full listing of computer's color palettes, see
List of palettes"
Computer systems that use an 4-bit or 8-bit
pixeldepth can display up to 16 or 256 colors simultaneously. Many personal computers in the early 1990s displayed at most 256 different colors, freely selected by software(either by the user or by a program) from their wider hardware's RGBcolor palette.
Usual selections of colors in limited subsets (generally 16 or 256) of the full palette includes some RGB level arrangements commomly used with the 8-bit palettes as "master palettes" or "universal palettes" (i.e., palettes for multipursose uses).
These are some representative software palettes, but any selection can be made in such type of systems.
For specific hardware color palettes, see the
List of monochrome and RGB palettes, List of 8-bit computer hardware palettes, the List of 16-bit computer hardware palettesand the List of videogame consoles palettesarticles.
Each palette is represented by an array of color patches. A one-pixel size version appears below each palette, to make it easy to compare palette sizes.
For each unique palette, an image color test chart and sample image (
truecolororiginal follows) rendered with that palette (without dithering) are given. The test chart shows the full 8-bit, 256 levels of the red, green, and blue ( RGB) primary colors and cyan, magenta, and yellow complementary colors, along with a full 8-bit, 256 levels grayscale. Gradients of RGB intermediate colors (orange, lime green, sea green, sky blue, violet and fucsia), and a full huespectrum are also present. Color charts are not gamma corrected.
Microsoft Windows default 20-color palette
RISC OS2.x and 3.x provided this 16-color palette [ [http://www.houseofmabel.com/puters/RISCOS2/ House of Mabel: RISC OS 2] ] :
This palette is constructed with six levels for red and blue primaries and seven levels for the green primary, giving 6×7×6 = 252 combinations. The index can be addressed by (42×R)+(6×G)+B, with R and B values in a range from 0 to 5 and G in a range from 0 to 6. The same case as the former, but with an added level of green due to the greater sensibility of the normal human eye to this frequency.
It does not provide true grays, but remaining indexes can be filled with four intermediate grays. In any case, there is little room for any other color.
6-8-5 levels RGB
Simple palette made doing every triplet RGB primaries having equal values as a continuous gradient from black to white through the full available palette entries. Here is the 8-bit, 256 levels palette:
Used to display pure
grayscale TIFFor JPEGimages, for example.
Color gradient palettes
Palettes made of a continuous color gradient from darkest to lightest arbitrary hues. The pixel data is treated as if it were grayscale, but the color table plays with RGB color combinations, not only gray. The relationship between the original luminance and the mapped one can vary, but the lighting scale is preserved along all the palette entries.
One very common case of such palettes is the
sepia tonepalette, which gives an image an old fashioned and aged look (left). Another gradient example, based on blue hues is presented here (right), but any hue or mixing of hues can be used. Many cell phones with built-in cameras have options to take colorized photos using this technique.
Arbitrary gradient color scales, usually 256 shades, with no relationship with real colors of a given image. They are employed to artificially colorize a grayscale image to reveal details and/or to map the pixel level values to amounts of some physical magnitude (
potential, temperature, altitude, etc.)
Note, in the example above, that new details can be seen as blue over magenta in the background's dark areas of the original photograph.
Here is the 8-bit, 256 color gradient palette used with the color test chart and the image sample above:
There exists many false color palettes, some of them standarized, used mainly in scientifical applications:
astronomyand radioastronomy, satellite land imaging, thermography, study of materials, tomographyand magnetic resonance imagingin medicine, etc.
*Color Lookup Table
X11 color names
Wikimedia Foundation. 2010.