This is a list of notable RGB hardware color palettes used on 16-bit computers, which were primarily manufactured from 1985 to 1995. Due to mixed-bit architectures, the n-bit distinction is not always a strict categorization.
Atari
ST series The Atari ST series has a digital-to-analog converter with 3-bits (eight levels) per RGB channel, featuring a 9-bit RGB palette (512 colors). Depending on the (proprietary) monitor type attached, it displays either 320×200 with 16-colors or 640×200 with 4-colors with a color monitor (or TV), or the high resolution 640×400 black and white mode with a monochrome monitor.
2-color (monochrome) mode is either black on white or white on black. The STE, Mega STE and TT have a digital-to-analog converter with 4-bits (sixteen levels) per RGB channel, featuring a 12-bit RGB palette (4096 colors) similar to the Commodore Amiga.
TT 030 The Atari TT also has 4-bits per RGB channel, for a 12-bit RGB palette (4096 colors) and in addition to the ST's modes, can use any 2 colors in 640x400 1 bit per pixel mode and 16 colours at 640x480. It also has a 320x480 256 color mode and a 1280x960 monochrome mode. The 256 color mode can either use a palette of colors picked from the 4096, or 256 shades of grey.
Falcon 030 The Atari Falcon 030 uses a 6-bits per channel, 64 level digital-to-analog converter to give an 18-bit RGB palette (262,144 colors), from which can be selected any 2, 4, 16, or 256 at a time. It also has a 16-bit (RGB565) highcolor mode able to display any of 65536 colors, though this is somewhat performance limiting.
Commodore
Amiga OCS The Original Chip Set (OCS) of the Commodore Amiga features a 12-bit RGB, 4,096-color palette. As the Amiga Copper programmable graphics coprocessor is capable of changing color lookup table entries on the fly during display, in practice the number of distinct colors visible on-screen may exceed static color lookup table sizes documented here.
5-bit The picture is divided in a series of bit planes, between 1 and 6 for horizontal resolutions of 320 (or up to 384 with overscan), and between 1 and 4 for horizontal resolutions of 640 (or up to 768 with overscan). For either horizontal resolution, the vertical resolution is either 200 (or up to 240 with overscan), or 400 (or up to 480 with overscan) if interlaced, for NTSC-compatible video modes; or 256 (or up to 288 with overscan), or 512 (or up to 576 with overscan) if interlaced, for PAL-compatible video modes. The color lookup table has up to 32 entries. So the different indexed color modes are from 1 to 5 bits pixel depth, 2-, 4-, 8-, 16- or 32-color out of 4,096.
6-bit When the sixth bit-plane is used, two extra color modes can be set: Extra Half-Brite (EHB) and Hold-And-Modify (HAM). In the EHB mode, when the sixth bit is set to on for any given pixel, the display hardware halves the brightness of said pixel. This allows the Amiga to display 64 colors instead of the standard 32, with the caveat being that the 32 extra colors cannot be arbitrarily selected, and must be darker versions of those already being displayed on screen In the HAM mode, the two higher bits of the 6-bits pixels are used as a four state command. Three of the states changes only the red, green or blue component of the pixel respect of the precedent in the scan line, and hold the other two RGB components. The new value for the modified color component is in the four lower bits. The remaining command state forces the pixel value to be one of the 16 first values of the palette, whose indice is in the four lower bits of the pixel. So it is very important to have a well selected palette, or the color will spread easily among consecutive pixels in the scan line of the image. This mode can display all of the 4,096 colors simultaneously.
Amiga ECS Amigas with the newer ECS chipset have the same color capabilities as the original OCS machines but have some screen resolution upgrades.
Amiga AGA
Apple
Apple IIGS Apple IIGS, along with full compatible graphic modes with the Apple II, features a custom Video Graphics Chip (VGC) which supports a 12-bit RGB, 4,096-color palette. It has an extended set of 320×200 and 640×200 graphic modes, (called Super High-Res modes by Apple) with different (and a bit complex) color modes:
320×200 with 16 palettes of 16 selected colors out of 4,096 each. Every single scan line can be assigned to one of the sixteen palettes, so it can have up to 16×16=256 different simultaneous colors (although some common colors like black and white are usually shared among the different palettes, giving fewer than 256 total different colors). The most simple way to use this mode is having a unique 16-color selection for the entire screen and assign it to all scan lines. Here are shown the sample image both using a single shared palette and using all the 16 palettes (in this case, by dividing the image into 16 strips): 640×200 with 16 palettes of 8 selected colors out of 4,096 each. Every single scan line can be assigned to one of the sixteen palettes, so it can have up to 8×16=128 different simultaneous colors (usually less due to shared colors). In a single scan line, even column pixels can have one of the first four colors of the line's assigned palette, and odd column pixels one of the last four colors of the eight. The most simple way to use this mode is having a unique 8-color selection for the entire screen with four duplicate colors (the same to both even and odd pixel columns) and assign it to all scan lines. Here are shown the sample image both with a single shared custom 4-color palette and with a single 8-color palette (black, blue, yellow, white, black (again), red, green, white (again)) to produce 13 dithered-by-hardware colors, ("dark blue", "dark yellow", "gray", "dark red", "magenta", "orange", "light red", "dark green", "cyan", "lime green", "light green", "light blue", and "light yellow") plus pure black and white. The last was the Apple IIGS Finder default mode and palette. Also, along with the one of 16 palettes, to each scan line the Apple IIGS VGC is able to assign individual 320 or 640 horizontal resolution independently. The closest output would be:
Sharp
X68000 The X68000, released in 1987, uses a 16-bit RGB palette. All 65,536 colors can be displayed simultaneously in resolutions up to 512x512, or 16 out of 65,536 colors at the highest resolution of 1024x1024.
IBM PC/AT and compatible systems
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