List of monochrome and RGB palettes

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For a full listing of computer's color palettes, see List of palettes

This list of monochrome and RGB palettes includes generic repertoires of colors (color palettes) to produce black-and-white and RGB color pictures by a computer's display hardware, not necessarily the total number of such colors that can be simultaneously displayed in a given text or graphic mode of any machine. RGB is the most common method to produce colors for displays; so these complete RGB color repertoires have every possible combination of R-G-B triplets within any given maximum number of levels per component.

For specific hardware and different methods to produce colors other than RGB, see the List of 8-bit computer hardware palettes, the List of 16-bit computer hardware palettes and the List of videogame consoles palettes. For various software arrangements and sorts of colors, including other possible full RGB arrangements within 8-bit color depth displays, see the List of software palettes.

Each palette is represented by a series of color patches. When the number of colors is low, a 1-pixel-size version of the palette appears below it, for easily comparing relative palette sizes. Huge palettes are given directly in one-color-per-pixel color patches.

For each unique palette, an image color test chart and sample image (truecolor original follows) rendered with that palette (without dithering) are given. The test chart shows the full 256 levels of the red, green, and blue (RGB) primary colors and cyan, magenta, and yellow complementary colors, along with a full 256-level grayscale. Gradients of RGB intermediate colors (orange, lime green, sea green, sky blue, violet, and fuchsia), and a full hue spectrum are also present. Color charts are not gamma corrected.

RGB 24bits palette sample image.jpg RGB 24bits palette color test chart.png

These elements illustrate the color depth and distribution of the colors of any given palette, and the sample image indicates how the color selection of such palettes could represent real-life images. These images are not necessarily representative of how the image would be displayed on the original graphics hardware, as the hardware may have additional limitations regarding the maximum display resolution, pixel aspect ratio and color placement. For simulated sample images for notable computers, see the List of 8-bit computer hardware palettes and List of 16-bit computer hardware palettes articles.


Monochrome palettes

These palettes only have some shades of gray, from black to white, both considered the most possible darker and lighter "grays", respectively. The general rule is that those palettes have 2n different shades of gray, where n is the number of bits needed to represent a single pixel.

Monochrome (1-bit)

Monochrome graphics displays typically have a black background with a white or light gray image, though green and amber monochrome monitors were also common. Such a palette requires only one bit per pixel.

Bilevel 1bit palette sample image.png Bilevel 1bit palette color test chart.png

Where photo-realism was desired, these early computer systems had a heavy reliance on dithering to make up for the limits of the technology.

Bilevel 1bit palette sample image - gimp dithered.png RGB 24bits palette color test chart - 1-bit dithered.png
Bilevel 1bit palette.png

In some systems, as Hercules and CGA graphic cards for the IBM PC, a bit value of 1 represents white pixels (light on) and a value of 0 the black ones (light off); others, like the Atari ST and Apple Macintosh with monochrome monitors, a bit value of 0 means a white pixel (no ink) and a value of 1 means a black pixel (dot of ink), which it approximates to the printing logic.

2-bit Grayscale

In a 2-bit color palette each pixel's value is represented by 2 bits resulting in a 4-value palette (22 = 4).

Grayscale 2bit palette sample image.png Grayscale 2bit palette color test chart.png

2-bit dithering:

Grayscale 2bit palette sample image - gimp dithered.png RGB 24bits palette color test chart - 2-bit dithered.png

It has black, white and two intermediate levels of gray as follows:

Grayscale 2bit palette.png

A monochrome 2-bit palette is used on:


4-bit Grayscale

In a 4-bit color palette each pixel's value is represented by 4 bits resulting in a 16-value palette (24 = 16):

Grayscale 4bit palette sample image.png Grayscale 4bit palette color test chart.png

4-bit grayscale dithering does a fairly good job of reducing visible banding of the level changes:

Grayscale 4bit palette sample image - gimp dithered.png RGB 24bits palette color test chart - 4-bit gray dithered.png
Grayscale 4bit palette.png

A monochrome 4-bit palette is used on:

8-bit Grayscale

Grayscale 8bits palette sample image.png Grayscale 8bits palette color test chart.png

In an 8-bit color palette each pixel's value is represented by 8 bits resulting in a 256-value palette (28 = 256). This is usually the maximum number of grays in ordinary monochrome systems; each image pixel occupies a single memory byte.

Grayscale 8bits palette.png

Most scanners can capture images in 8-bit grayscale, and image file formats like TIFF and JPEG natively support this monochrome palette size.

Alpha channels employed for video overlay also use (conceptually) this palette. The gray level indicates the opacity of the blended image pixel over the background image pixel.

Regular RGB palettes

Here are grouped those full RGB hardware palettes that have the same number of binary levels (i.e., the same number of bits) for every red, green and blue components using the full RGB color model. Thus, the total number of colors are always the number of possible levels by component, n, raised to a power of 3: n×n×n = n3.

3-bit RGB

RGB 3bits palette sample image.png RGB 3bits palette color test chart.png

3-bit RGB dithering:

RGB 24bits palette sample image - 3-bit RGB.png RGB 24bits palette color test chart - 3-bit RGB dithered.png

Systems with a 3-bit RGB palette use 1 bit for each of the red, green and blue color components. That is, each component is either "on" or "off" with no intermediate states. This results in an 8-color palette ((21)3 = 23 = 8) that have black, white, the three RGB primary colors red, blue and green and their correspondent complementary colors cyan, magenta and yellow as follows:

RGB 3bits palette.png

The color indices vary between implementations; therefore, index numbers are not given.

The 3-bit RGB palette is used by:


6-bit RGB

RGB 6bits palette sample image.png RGB 6bits palette color test chart.png

Systems with a 6-bit RGB palette use 2 bits for each of the red, green, and blue color components. This results in a (22)3 = 43 = 64-color palette as follows:

RGB 6bits palette.png

6-bit RGB systems include the following:


9-bit RGB

RGB 9bits palette sample image.png RGB 9bits palette color test chart.png

Systems with a 9-bit RGB palette use 3 bits for each of the red, green, and blue color components. This results in a (23)3 = 83 = 512-color palette as follows:

RGB 9bits palette.png

9-bit RGB systems include the following:


12-bit RGB

RGB 12bits palette sample image.png RGB 12bits palette color test chart.png

Systems with a 12-bit RGB palette use 4 bits for each of the red, green, and blue color components. This results in a (24)3 = 163 = 4096-color palette as follows:

RGB 12bits palette.png

12-bit RGB systems include the following:


15-bit RGB

RGB 15bits palette sample image.png RGB 15bits palette color test chart.png

Systems with a 15-bit RGB palette use 5 bits for each of the red, green, and blue color components. This results in a (25)3 = 323 = 32,768-color palette (commonly known as Highcolor) as follows:

RGB 15bits palette.png

15-bit systems include:


18-bit RGB

RGB 18bits palette sample image.png RGB 18bits palette color test chart.png

Systems with an 18-bit RGB palette use 6 bits for each of the red, green, and blue color components. This results in a (26)3 = 643 = 262,144-color palette as follows:

RGB 18bits palette.png

18-bit RGB systems include the following:


24-bit RGB

RGB 24bits palette sample image.jpg RGB 24bits palette color test chart.png

Often known as truecolor and millions of colors, 24-bit color is the highest color depth normally used, and is available on most modern display systems and software. Its color palette contains (28)3 = 2563 = 16,777,216 colors. This is approximately the number of individual colors the human eye can distinguish within the limited gamut of a typical display[citation needed].

The complete palette needs a squared image of 4,096 pixels wide (50MB in memory), and there is not enough room in this page to show it at full. An image of the full palette can be found here.

This can be imagined as 256 stacked squares like the following, every one of them having the same given value for the red component, from 0 to 255.

The color transitions in these patches must be seen as continuous. If you see color stepping (banding) inside, then probably your display is using a Highcolor (15- or 16- bits RGB, 32,768 or 65,536 colors) mode or lesser.

RGB 24bits palette R0.png
Red = 0		 RGB 24bits palette R85.png
Red = 85 (1/3 of 255)
RGB 24bits palette R170.png
Red = 170 (2/3 of 255)		 RGB 24bits palette R255.png
Red = 255

This is also the number of colors used in true color image files, like Truevision TGA, TIFF, JPEG (the last internally encoded as YCbCr) and Windows Bitmap, captured with scanners and digital cameras, as well as those created with 3D computer graphics software.

24-bit RGB systems include:


30-bit RGB

(No simulation available)

Some newer graphics cards support 30-bit RGB and higher. Its color palette contains (210)3 = 10243 = 1,073,741,824 colors. However, there are few operating systems or applications that support this mode yet. For some people, it may be hard to distinguish between higher color palettes than 24-bit color offers. However, the range of luminance, or gray scale, offered in a 30-bit color system would have 1,024 levels of luminance rather than the 256 of the common standard 24-bit, to which the human eye is more sensitive than to hue.

Non-regular RGB palettes

These also are full RGB palette repertories, but either they do not have the same number of levels for every red, green and blue components, or they are bit levels based. Nevertheless, all of them are used in very popular personal computers.

For further details on color palettes for these systems, see the article List of 8-bit computer hardware palettes.

4-bit RGBI

RGBI 4bits palette sample image.png RGBI 4bits palette color test chart.png

The 4-bit RGBI palette is similar to the 3-bit RGB palette but adds one bit for intensity. This results in each of the colors of the 3-bit palette to have a dark and bright variant giving a total of 23×2 = 16 colors.

This 4-bits RGBI schema is used in several platforms with variations, so the table given below is a simple reference for the palette richness, and not an actual implemented palette. For this reason, no numbers are assigned to each color, and color order is arbitrary.

RGBI 4bits palette.png

Note that "dark white" is a lighter gray than "bright black".

The 4-bits RGBI palettes are used by:

  • Color Graphics Adapter, with brown instead of dark yellow). On CGA, setting a color "bright" added ⅓ of the maximum to all three channels' brightness, so the "bright" colors were whiter shades of their 3-bit counterparts. Each of the other bits increased a channel by ⅔, except that dark yellow had only ⅓ green and was therefore brown instead of ochre.
    • The CGA palette was the default for EGA, VGA and Microsoft Windows 3.x (on the IBM PC and compatibles), although other palettes were available.
  • MOS Technology VDC (on the Commodore 128)
  • ZX Spectrum (with two black, black with bright is the same as black without bright)
  • TI 99/4A / MSX (These use the TMS9918 video chip. The colors do not conform to the image above, but has instead: transparency, black, medium green, light green, dark blue, dark purple, brown, cyan, dark red, orange, dark yellow, light yellow, dark green, medium purple, gray, and white.)
  • Sharp MZ 800


3-level RGB

AmstradCPC palette sample image.png AmstradCPC palette color test chart.png

The 3-level ('not' bits) RGB uses three level for every red, green and blue color components, resulting in a 33 = 27 colors palette as follows:

AmstradCPC palette.png

This palette is used by:


3-3-2 bit RGB

MSX2 Screen8 palette sample image.png MSX2 Screen8 palette color test chart.png

The 3-3-2 bit RGB use 3 bits for each of the red and green color components, and 2 bits for the blue component, due to the lesser sensitivity of the common human eye to this primary color. This results in an 8×8×4 = 256-color palette as follows:

MSX2 Screen8 palette.png

This palette is used by

  • The MSX2 series of personal computers.
  • Palette 4 of the IBM PGC (palette 2 gives 2-3-3 bit RGB and palette 3 gives 3-2-3 bit RGB).
  • VGA built-in output of the Digilent Inc. NEXYS 2, NEXYS 3 and BASYS2 FPGA boards.
  • The Uzebox gaming console
  • SGI Indy 8-bit XL graphics
  • The Tiki 100 personal computer (only 16 colors can be displayed simultaneously)


16-bit RGB

RGB 16bits palette sample image.png RGB 16bits palette color test chart.png

Most modern systems support 16-bit color. It is sometimes referred to as Highcolor (along with the 15-bit RGB), medium color or thousands of colors. It utilizes a color palette of 32×64×32 = 65,536 colors. Usually, there are 5 bits allocated for the red and blue color components (32 levels each) and 6 bits for the green component (64 levels), due to the greater sensitivity of the common human eye to this color. This doubles the 15-bit RGB palette.

The 16-bit RGB palette using 6 bits for the green component:

RGB 16bits palette.png

The Atari Falcon and the Extended Graphics Array (XGA) for IBM PS/2 use the 16-bit RGB palette.

It must be noticed that not all systems using 16-bit color depth employ the 16-bit, 32-64-32 level RGB palette. Platforms like Sharp X68000 or the Neo Geo videogame console employs the 15-bit RGB palette (5 bits are used for red, green, and blue), but the last bit specifies a less significant intensity or luminance. The 16-bit mode of the Truevision TARGA/AT-Vista/NU-Vista graphic cards and its associated TGA file format also uses 15-bit RGB, but it devotes its remaining bit as a simple alpha channel for video overlay. The Atari Falcon can also be switched into a matching mode by setting of an "overlay" bit in the graphics processor mode register when in 16-bit mode, meaning it can actually display in either 15- or 16-bit color depth depending on application.


See also

Notes

  1. ↑ Lua error in package.lua at line 80: module 'strict' not found.

External links and sources

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