List of 8-bit computer hardware graphics

Systems with a 3-bit RGB palette use 1 bit for each of the red, green and blue color components.

A common selection has 3 bits (from LSB to MSB) directly representing the 'Red', 'Green' and 'Blue' (RGB) components in a number from 0 to 7.

Some implementations had only 15 effective colors due to the "dark" and "bright" variations of black being displayed identically.

[4] The color number (0 to 7) can be employed with the following BASIC statements to choose: And a value of 0 or 1 with the following statements to choose: number name name The original IBM PC launched in 1981 features an Intel 8088 CPU which has 8-bit data bus technology, though internally the CPU has a fully 16-bit architecture.

The resulting displayed colors on RGB monitors are shown below: A few earlier non-IBM compatible CGA monitors lack the circuitry to decode color numbers as of four levels internally, and they cannot show brown and dark gray.

For mode 4, two palettes can be chosen: green/red/brown and cyan/magenta/white; the difference is the absence or presence of the blue signal in all three colors.

The palette for BIOS video mode 5 is always cyan/red/white: blue is always on, and red and green each are controlled directly by one of the two bits of the pixel color value.

The selected intensity setting simply controls the "I" output signal to the RGBI monitor for all colors in the palette.

For Thomson computers, a popular brand in France, the most common display modes are 320×200, with 8×1 attribute cells with 2 colors.

This is done by a PROM circuit, where a two bit mask controls colour mixing ratios of 0%, 33%, 66% and 100% of the saturated hue.

Displayed colors are only approximate due to different transfer and color spaces used on web pages (sRGB) and analog video (BT.601) Actual colour on emulators and later models seems to have been tweaked, with normal Blue and Red being fully saturated.

There are spatial constraints ("attribute" areas) for different colors, consisting of 2x3 pixel groups.

[19] The Amstrad CPC 464/664/6128 series of computers generates the available palette with 3 levels (not bits) for every RGB primary.

It supports 3 different resolutions with 256, 512 or 1024 by 256 pixels and 16, 4, or 2 colors respectively (freely selectable from the full 256-color palette).

The attribute graphics mode provides a 320×256 pixel resolution with 16 colors, selectable from a palette of 256.

The MSX2+ series (released in 1988) features a Yamaha V9958 video chip which manages a 15-bit RGB palette internally encoded in YJK (up to 19,268 different colors from the 32,768 theoretically possible)[22] and has additional screen modes.

As a result of every four pixels sharing a chroma value, in mode 12 it is not possible to have vertical lines of a single color.

This section covers systems that generate color directly as composite video, closely related with display on analog CRT TVs.

The ANTIC chip has an instruction set to run programs (called display lists) which permits many more colors on the screen at once.

[25] High-res mode palette For all the following computers from Commodore, the U and V coordinates for the composite video colors are always the cosine and the sine, respectively, of angles multiple of 22.5 degrees (i.e. a quarter of 90°), as the engineers were inspired by the NTSC color wheel, a radial way to figure out the U and V coordinates of points equidistant from the center of the chroma plane, the gray.

Consumers in Europe (which uses PAL) considered the Commodore colors to be more "washed out" and less vivid than those provided by computers such as the ZX Spectrum.

[26][27][28] The VIC-20 uses a MOS Technology VIC chip which produces a 16-color YPbPr composite video palette.

When displayed over an analog NTSC composite video output, the actual resulting colors are more vivid.

It has a palette of 121 YPbPr composite video colors[32] consisting of sixteen hues (including black and white) at eight luminance levels.

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).

Simulated images Notes: The TMS9918 is a Video Display Controller (VDC) manufactured by Texas Instruments and introduced in 1979.

(chroma) with 3 possible levels, based on the YPbPr colorspace, and then converted for output into a NTSC analog signal.

The hardware palette has 9 colors: black, green, yellow, blue, red, buff (almost-but-not-quite white), cyan, magenta, and orange.

Taking the place of the graphics and memory hardware of the previous machines is an application-specific integrated circuit called (officially) the Advanced Color Video Chip (ACVC) or (unofficially) the Graphics Interrupt Memory Enhancer (GIME).

Two bits are used for each of Red, Green and Blue and give a similar result to a normal 6-bit RGB palette (as seen with the IBM EGA or Sega Master System); the seventh bit encodes for "brightness", which has a similar but more subtle effect to the Spectrum, increasing the output of all three channels by half the intensity of the lower bits of the main six (in this way, it does make a genuine 128 colors — rather than 127 colors with "two blacks" and only a 7-level grayscale).