List of monochrome and RGB color formats


This list of monochrome and RGB palettes includes generic repertoires of colors to produce black-and-white and RGB color pictures by a computer's display hardware. 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.
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 rendered with that palette are given. The test chart shows the full 256 levels of the red, green, and blue primary colors and cyan, magenta, and yellow complementary colors, along with a full 256-level grayscale. Gradients of RGB intermediate colors, and a full hue spectrum are also present. Color charts are not gamma corrected.
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.
Implementation of these formats is specific to each machine. Therefore, the number of colors that can be simultaneously displayed in a given text or graphic mode might be different. Also, the actual displayed colors are subject to the output format used - PAL or NTSC, composite or component video, etc. - and might be slightly different.
For simulated images and specific hardware and alternate 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 [video game console 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.

Monochrome palettes

These palettes only have some shades of gray, from black to white. 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 grayscale)

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.
Where photo-realism was desired, these early computer systems had a heavy reliance on dithering to make up for the limits of the technology.
In some systems, as Hercules and CGA graphic cards for the IBM PC, a bit value of 1 represents white pixels and a value of 0 the black ones ; others, like the Atari ST and Apple Macintosh with monochrome monitors, a bit value of 0 means a white pixel and a value of 1 means a black pixel, 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.
2-bit dithering:
It has black, white and two intermediate levels of gray as follows:
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 :
4-bit grayscale dithering does a fairly good job of reducing visible banding of the level changes:
A monochrome 4-bit palette is used on:

8-bit Grayscale

In an 8-bit color palette each pixel's value is represented by 8 bits resulting in a 256-value palette. This is usually the maximum number of grays in ordinary monochrome systems; each image pixel occupies a single memory byte.
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 this palette. The gray level indicates the opacity of the blended image pixel over the background image pixel.

Dichrome palettes

16-bit RG palette

The RG or red–green color space is a color space that uses only two primary colors: red and green. It was used on early color processes for films.
It was used as an additive format, similar to the RGB color model but without a blue channel, on processes such as Kinemacolor, Prizma, Technicolor I, Raycol, etc., producing shades of black, red, green and yellow. Alternatively, it was used as a subtractive format on Brewster Color I, Kodachrome I, Prizma II, Technicolor II, etc., producing shades of transparent, red, green and black.
Until recently, its primary use was in low-cost light-emitting diode displays in which red and green tended to be far more common than the still nascent blue LED technology, but full-color LEDs with blue have become more common in recent years.
ColorCode 3-D, a anaglyph stereoscopic color scheme, uses the RG color space to simulate a broad spectrum of color in one eye, while the blue portion of the spectrum transmits a black-and-white image to the other eye to give depth perception.

Regular RGB palettes

Here are grouped those full RGB hardware palettes that have the same number of binary levels 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

3-bit RGB dithering:
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 that has black, white, the three RGB primary colors red, green and blue and their correspondent complementary colors cyan, magenta and yellow as follows:
The color indices vary between implementations; therefore, index numbers are not given.
The 3-bit RGB palette is used by:

6-bit RGB

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

9-bit RGB

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

12-bit RGB

Systems with a 12-bit RGB palette use 4 bits for each of the red, green, and blue color components. This results in a 3 = 163 = 4096-color palette. 12-bit color can be represented with three hexadecimal digits, also known as shorthand hexadecimal form, which is commonly used in web design. The palette is as follows:
12-bit RGB systems include the following:
The Allegro library supported in the version 4, an emulated 12-bit color mode example code, using 8-bit indexed color in VGA/SVGA. It used two pixels for each emulated pixel, paired horizontally, and a specifically adapted 256-color palette. One range of the palette was many brightnesses of one primary color, and another range of the other two primaries mixed together at different amounts and brightnesses. It effectively reduced the horizontal resolution by half, but allowed a 12-bit "true color" in DOS and other 8-bit VGA/SVGA modes. The effect also somewhat reduced the total brightness of the screen.

15-bit RGB

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

18-bit RGB

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

21-bit RGB

21-bit RGB has 7 bits for red green and blue. 21-bit RGB has a total of 2,097,152 colors.
21-bit RGB systems include the following:

24-bit RGB

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 3 = 2563 = 16,777,216 colors. 24-bit color can be represented with six hexadecimal digits.
The complete palette needs a squared image of 4,096 pixels wide, and there is not enough room in this page to show it at full.
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 color stepping inside is visible, then probably the display is set to a Highcolor mode or lesser.
This is also the number of colors used in true color image files, like Truevision TGA, TIFF, JPEG 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

Some newer graphics cards support 30-bit RGB and more. Its color palette contains 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. This reduces the banding effect for gradients across large areas.

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

The 4-bit RGBI palette is similar to the 3-bit RGB palette but adds one bit for intensity. This allows each of the colors of the 3-bit palette to have a dark and bright variant, potentially giving a total of 23×2 = 16 colors. However, some implementations had only 15 effective colors due to the "dark" and "bright" variations of black being displayed identically.
This 4-bit 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.
Note that "dark white" is a lighter gray than "bright black" in this example.

IBM PC graphics

A common use of 4-bit RGBI was on IBM PCs and compatible computers that used a 9-pin DE-9 connector for color output. These computers used a modified "dark yellow" color that appeared to be brown. On displays designed for the IBM PC, setting a color "bright" added 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, except that dark yellow had only green and was therefore brown instead of ochre.
PC graphics standards using this RGBI mode include:
The CGA palette is also used by default by IBM's later EGA, MCGA, and VGA graphics standards for backward compatibility, but these standards allow the palette to be changed, since they either provide extra video signal lines or use analog RGB output.
The MOS Technology 8563 and 8568 Video Display Controller chips used on the Commodore 128 series for its 80-column mode also used the same palette used on the IBM PC, since these chips were designed to work with existing CGA PC monitors.

Other uses

Other systems using a variation of the 4-bit RGBI mode include:
  • The ZX Spectrum series of computers, which lack distinct "dark" and "light" black colors, resulting in an effective 15-color palette.
  • The Sharp MZ-800 series computers.
  • The Thomson MO5 and TO7 where the intensity bit created a variation of saturation.
  • The Mattel Aquarius and AlphaTantel where the intensity bit created a variations of brightness and saturation. There are three bits for the RGB components and an intensity bit that controls a variation of the base color.
  • The Magnavox Odyssey 2 is equipped with an Intel 8244 (NTSC) or 8245 (PAL) custom IC, and uses a 4-bit RGBI color palette. Bits 0 to 2 define Grid color, bits 3 to 5 define Background color, bit 6 defines Grid luminance and bit 7 is unused.
  • The Tandy 2000 Graphics Adapter with Color Graphics Option.

3-level RGB

3-level RGB dithering:
The 3-level, or 1-trit RGB uses three levels for every red, green and blue color component, resulting in a 33 = 27 colors palette as follows:
This palette is used by:

8-bit RGB

3-3-2 bit RGB or 8-8-4 level RGB

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 human eyes having lesser sensitivity to blue. This results in an 8×8×4 = 256-color palette as follows:
This palette is used by:

3-2-3 bit RGB or 8-4-8 level RGB

The 3-2-3 bit RGB palette uses 3 bits for the red color component, 2 bits for the green, and 3 bits for the blue. This results in an 8×4×8 = 256-color palette.
This palette is used by:

2-3-3 bit RGB or 4-8-8 level RGB

The 2-3-3 bit RGB palette uses 2 bits for the red color component, and 3 bits for the green and blue components. This results in an 4×8×8 = 256-color palette.
This palette is used by:

5-5-4 bit RGB or 32-32-16 level RGB

The 5-5-4 bit RGB palette uses 5 bits for the red and green color components, and 4 bits for the blue component, due to the human eyes having lesser sensitivity to blue. This results in an 32x32x16 = 16,384-color palette.
Unlike other RGB palettes, in 5-5-4 bit RGB, the bits are bitmasks of the full 8-bit components, and not fractions of them. This means the highest possible value represents #f8f8f0, rather than the expected #ffffff.
This palette is used by:
  • Scratch 2.0 and early 3.0 programming language

16-bit RGB (also known as RGB565)

Most modern systems support 16-bit color. It is sometimes referred to as High color, 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 and 6 bits for the green component, 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:
The Atari Falcon and the Extended Graphics Array for IBM PS/2 use the 16-bit RGB palette.
Not all systems using 16-bit color depth employ the 16-bit, 32-64-32 level RGB palette. Platforms like the Sharp X68000 home computer or the Neo Geo video game console employs the 15-bit RGB palette, 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.

Color palette comparison side-by-side

Basic color palettes

4-bit grayscale

0x00x10x20x30x40x50x60x70x80x90xA0xB0xC0xD0xE0xF

4-bit RGBI


3 level RGB


Advanced color palettes

8-bit RGB (VGA)

0x000x010x020x030x040x050x060x070x080x090x0A0x0B0x0C0x0D0x0E0x0F
0x100x110x120x130x140x150x160x170x180x190x1A0x1B0x1C0x1D0x1E0x1F
0x200x210x220x230x240x250x260x270x280x290x2A0x2B0x2C0x2D0x2E0x2F
0x300x310x320x330x340x350x360x370x380x390x3A0x3B0x3C0x3D0x3E0x3F
0x400x410x420x430x440x450x460x470x480x490x4A0x4B0x4C0x4D0x4E0x4F
0x500x510x520x530x540x550x560x570x580x590x5A0x5B0x5C0x5D0x5E0x5F
0x600x610x620x630x640x650x660x670x680x690x6A0x6B0x6C0x6D0x6E0x6F
0x700x710x720x730x740x750x760x770x780x790x7A0x7B0x7C0x7D0x7E0x7F
0x800x810x820x830x840x850x860x870x880x890x8A0x8B0x8C0x8D0x8E0x8F
0x900x910x920x930x940x950x960x970x980x990x9A0x9B0x9C0x9D0x9E0x9F
0xA00xA10xA20xA30xA40xA50xA60xA70xA80xA90xAA0xAB0xAC0xAD0xAE0xAF
0xB00xB10xB20xB30xB40xB50xB60xB70xB80xB90xBA0xBB0xBC0xBD0xBE0xBF
0xC00xC10xC20xC30xC40xC50xC60xC70xC80xC90xCA0xCB0xCC0xCD0xCE0xCF
0xD00xD10xD20xD30xD40xD50xD60xD70xD80xD90xDA0xDB0xDC0xDD0xDE0xDF
0xE00xE10xE20xE30xE40xE50xE60xE70xE80xE90xEA0xEB0xEC0xED0xEE0xEF
0xF00xF10xF20xF30xF40xF50xF60xF70xF80xF90xFA0xFB0xFC0xFD0xFE0xFF