List of 8-bit computer hardware palettes


List of 8-bit computer hardware palettes

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

This is a list of color palettes of some of the most popular early 8-bit personal computers and terminals, roughly those manufactured from 1975 to 1985. Although some of them use RGB palettes, are more common specific hardware-implemented 4, 16 or more colors palettes: not bit nor level combinations of RGB primaries, but fixed ROM/circuitry colors selected by the manufacturer. Also, the list does not include obscure palettes, such as those available only through special adjustment and/or CPU assisted techniques (flickering, palette swapping, etc.), except where noted.

For color palettes of 16-bit personal computers, see the List of 16-bit computer hardware palettes article.

For current RGB display systems for 32-bit and better PCs (Super VGA, etc.), see the 16-bit RGB for HighColor ("thousands") and 24-bit RGB for TrueColor ("millions of colors") modes.

It must be noted that this "n"-bit distinction is not intended as a true strict categorization of such machines, due to mixed architectures also exists (16-bit processors with 8-bit data bus, for example). The distinction is more related with a broad 8-bit computer "age" or "generation" (around 1975-1985) and its associated state of the art in color display capabilities. In any case, every computer listed here share similar 8-bit technology, except where noted.

For various software arrangements and sorts of colors, see the List of software palettes article.

For video game consoles, see the List of videogame consoles palettes article.

For a more complete and technical description of the computer's hardware video capabilities, see the List of home computers by video hardware.

They are listed the original model of every system, which implies that enhanced versions, clones and compatibles also supports the original's one palette.

For every model, their main different graphical color modes are listed based exclusively in the way they handle colors on screen, not all their possible different screen modes (text modes or resolution modes that shares the same color schemes).

Every palette it's represented with a series of color patches and are complemented with a listling of color numbers/indices and names, and other technical details about how the colors are produced and/or used by the computer's display video subsystem.

For each unique palette, an image color test chart and sample image (TrueColor original follows) rendered with that palette (without dithering) are given; color charts for palettes that already exists in other articles are not shown here. The test chart shows the full 8-bits, 256 levels of the red, green and blue (RGB) primary colors and cyan, magenta and yellow complementary colors, along with a full 8-bits, 256 levels grayscale. Gradients of RGB intermediate colors (orange, lime green, sea green, sky blue, violet and fucsia), and a full hue's spectrum are also present. Color charts are not gamma corrected.

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Although a bit disordered, some facts can be established:

*there are five levels for the luminance and five levels (two negatives, zero and two positives) for the chroma;
*colors 15 to 8 are the exact YPbPr complementary from the 0 to 7 (also their binary complements), so only eight colors are actually implemented and the rest obtained by inverting the YPbPr levels (hence the duplication of the gray at indexes 5 and 10);
*PbPr levels are chosen to get a regular distribution of the colors in the YPbPb color space within 16 entries and having the maximum (±Pb,±Pr) colors at Y=0.5.

The original Apple II has two graphic modes, along with a 40 columns text mode and some mixed graphic+text modes.

*Low resolution 40×48, 16-color graphic mode, with a 7:4 pixel aspect ratio.

When a RF modulator is employed to plug the Apple II to a NTSC TV set, many colors vary, and dramatically the brown and light blue, which when converted from YCbCr to YIQ color space by the RF modulator and to RGB by the TV built-in demodulator, lie deeply outside of the RGB gamut. The first image simulates native composite video monitor display, and the second NTSC TV display:

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*High resolution 280×196, 6-color mode.

In fact, high resolution mode is able to light on the pixels only in four colors: purple, green, orange and medium blue (pixels off are always black). Pixels on at even columns can be purple or blue, and at odd columns can be green or orange, and any of this purple-green or blue-orange color pairs can be selected for every seven consecutive pixels. A single pixel on also spreads through the half of the aside surrounding pixels. So when a purple-green or green-purple (or blue-magenta/magenta-blue) pixel pair are both on, this results in a on-screen mixed 2:1 aspect ratio "white pixel", and this is the sixth "color".

Due these color arrangements, the high resolution mode is usually documented to have a "practical resolution" of 140×192 instead of 280×196. It is more simply to think this way for programmers but not "more exact", so some "surprises" usually arise: a vertical line can be of a pure solid color when it has an odd number (1, 3, 5...) of pixels wide alternatively on and off (the off pixels seem to be "on" by the color spread of the aside on ones), but can be "white" when it has any number greater than one of pixels wide, all on; when two vertical, one pixel wide blue and green or orange and purple lines are drawn together, they also becomes colorized bluish, redish, yellowish or greenish "white", depending on the combination, etc.

The way to produce colors in high resolution mode is a pure analog tricky collateral effect. When RGB monitors and adapters become available for the Apple IIgs, users felt than the "good oldies" high resolution software and games do not look the same. But for this time, the Apple IIgs was able to use 4,096 RGB colors with new software, and the original-compatible high resolution 6-color mode was then considered outdated. The first image simulates native composite video monitor display, and the second a RGB monitor display:

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Commodore

For all the following computers of this brand, the Pb and Pr coordinates for the YPbPr composite video colors are always the cosine and the sine, respectively, of angles multiple of 22.5 degrees (i.e. a quarter of 90°), due to the engineerers were inspired by the NTSC color wheel, a radial way to figure out the Pb and Pr coordinates of points equidistant from the center of the chroma plane, the gray.

VIC-20

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The MOS Technology VIC-II is used in the Commodore 64 (and Commodore 128 in 40-column mode), and features a 16-color YPbPr composite video palette [ [http://www.pepto.de/projects/colorvic/ All you ever wanted to know about the colors of the commodore 64 ] ] .

Here are shown the correspondent RGB equivalents at a saturation level of 34%. See the Notes on composite video colors section to convert relative YPbPr colors to RGB colors.

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Note: every YPbPr color marked with an asterisk (*) are out of the RGB gamut. This was intentionally do by designers to achieve the maximum number of colors for composite video monitors.

Note: black has always a Y luminance level of 0, so ignore the column's header values.

The Commodore 16 and Plus/4 have two graphic modes very similar to those of the Commodore 64: Multicolor and High Resolution.

* In the Multicolor 160×200, 121-color mode, every cell of 4×8, 2:1 aspect ratio pixels can have one of four colors: two shared with the entire screen and the two background and foreground colors of the correspondent text mode character, all of them freely selectable among the entire 121-color palette (hue 0 to 15 and luminance 0 to 7 are set individually for any of them).

* In the High Resolution 320×200, 121-color mode, every cell of 8×8 pixels can have one of the two background and foreground colors of the correspondent text mode character, both freely selectable among the entire 121-color palette (again setting both the hue and the luminance).

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inclair

ZX Spectrum

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The Amstrad CPC 464/664/6128 series of computers generate the available palette with 3-levels (not bits) for every RGB primary. Thus, there are 27 different RGB combinations, from which 16 can be simultaneously displayed in low resolution mode, four in medium resolution mode and two in high resolution mode. [ [http://www.cantrell.org.uk/david/tech/cpc/cpc-firmware/firmware.pdf "The Amstrad CPC Firmware Guide"] ] .

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There is no apparent logic in this color selection.

The MSX have two text modes and two graphic modes. The MSX BASIC Screen 3 mode is a low resolution 64×48 pixels, 15-color mode, in which every pixel can be any of the colors. The Screen 2 mode is a high resolution 256×192 pixels, 15-color mode in which every eight consecutive pixels can be one of two out of 15 posible colors.

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MSX2

The MSX2 series features a Yamaha V9938 video chip which manages a 9-bit RGB palette (512 colors) and have some extended graphic modes. Although its graphical capabilities are similar, or even better than of those of 16-bit personal computers, MSX2 and MSX2+ (see below) are pure 8-bit machines.

The Screen 8 mode consists in a high resolution 256×212 pixels with 8-bit depth, 256 colors [Bits M1-M5 of VDP Register 0 and 1: Video Screen modes, Screen 8 from [http://www.work.de/nocash/portar.htm "Portar MSX Tech Doc"] ] . Bits in every byte are mapped (LSB to MSB): two for blue (four levels), three for red (eight levels) and three for green (again, eight levels). The higher order bits contain the brighter primary color (green) and the lower order bits contain the darker (blue). This mode has the half of the colors that the entire palette, and can be considered a proper palette in its own right.

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The Screen 12 mode is similar to the 10 & 11 modes, but it devoted five bits to encode 32 levels of luminance for every pixel, so it do not have a flag bit to switch to an indexed color. Thus, with this YJK encoding 19,268 different colors can be displayed simultaneously with only 8-bit pixel depth. Again, the full YJK 19,268 color palette follows:

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A few earlier non-IBM compatible CGA monitors lack the circuitry to decode color numbers as of four levels internally, and they cannot to show brown and dark grey. The above palette is displayed in such monitors as follows:

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PCjr and Tandy 1000 series

Although not fully compatible with the original IBM PC, the IBM PCjr and their near compatible Tandy 1000 series competitors feature a graphic chip known as "Video Gate Array" (not to be confused with the most widely known Video Graphics Array, despite of the fact that both share the same achronym VGA), which is able to show all 16 CGA colors simultaneously on screen in the extended low-res graphic modes 160×100 and 160×200, and mid-res 320×200. Here is the sample image using their exclusive low-res 160×200 mode, 2:1 pixel ratio:

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They also support an additional high-res 640×200 mode using any of the same 4 color mid-res 320×200 CGA palettes (see the CGA section above).

Notes

ee also

*Palette (computing)
*Indexed color
*Color Lookup Table
*Color depth
*Computer display
*List of home computers by video hardware


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