|Apple II Low Resolution Graphics Example - Lemonade Stand|
|Apple II High Resolution Graphics Example #1 - Ultima|
With composite artifact color, the color carrier signal is sent. The phase of the signal oscillates from 180 degrees to 270 degrees, 0 degrees, 90 degrees and back to 180 degrees for each color clock. The pixels are sent at twice the frequency of the color clock, and depending on where on the screen the pixel is, this will show the combination of the two nearest phase shifts. Thus, in the original Apple II, you can obtain a green from the combination of 90 and 180 degrees (~135 degrees) and magenta from 270 and 0/360 degrees (~315 degrees). Soon, the designers of the Apple II figured out how to use the eighth bit of each memory location to delay the pixel clock by half a clock, giving blue (~45 degrees) and orange (~225 degrees) artifact colors. Visually, a memory location with blue/orange colors will appear slightly shifted compared to a memory location above or below with green/magenta colors.
Due to the lack of bandwidth of an NTSC monitor, instead of getting colors alternating with black, you will see mostly solid colors. When the first pixel is set to color, the color carrier does not have time to fully transition back to black for the second color when the third pixel is also set to color. Thus you get a mostly solid color, however the better your monitor and connection, the more likely you will see lines between pixels.
|Apple II High Resolution Graphics Example #2 - Wasteland|
|Apple II Double High Resolution Graphics Example - Might and Magic II: Gates to Another World|
At least seventy games support DHGR graphics, but not all are very playable on a 1MHz 6502/65C02 and many of these games pale in comparison to versions of these games for other platforms. Maniac Mansion, Sierra AGI Quest games and many arcade ports fall into this category. Still, there are several games originally developed for the Apple IIe and its DHGR mode, including Prince of Persia (limited), Dragon Wars, Might and Magic II, King's Bounty, Air Heart, Into the Eagle's Nest, Legend of Blacksilver.
|Atari 8-bit Color Composite Graphics Example #1 - Exodus: Ultima III|
|Atari 8-bit Composite Color Example #2 - Choplifter!|
Discussion of IBM PC Composite Color moved to its own blog entry : http://nerdlypleasures.blogspot.com/2013/11/ibm-pc-color-composite-graphics.html
|Tandy TRS-80 Color Computer Color Composite Graphics Example - Donald Duck's Playground|
In 1982, Tandy released its Color Computer. Its graphics system had definite similarities with the CGA card, its sound system was very simple and it was not very attractive to game developers. It supported a 256x192 artifact color mode, with blue and orange in addition to black and white. Many games used this mode due to the limitations of the direct color modes. Essentially the graphics look very similar to the Apple II's HGR graphics, but are more limited due to the absence of any primary colors other than blue and orange. The Color Computer 3 has far superior graphic capabilities, enough so that a nearly-perfect port of Donkey Kong was created for it.
Artifact color does not work with S-Video (which can be obtained from the Atari 800), as that connector separates the luminance and chrominance signals. Artifact color relies on the demodulation of the combined luminance and chrominance signals. You will see monochrome colored pixels with serrated graphics where color was intended if you use S-Video.
Artifact color was designed for NTSC-standard monitors. No PAL home computer ever used it. The Apple II Europlus does not output color without a special "PAL color card." The Apple IIe and later models have the PAL color card built in. The video output is not as good as with an NTSC monitor. There is no "PAL" CGA card. The PAL Atari 8-bit machines would have treated the 320x192 as a strictly monochrome mode. While the TRS-80 CoCo may not have been widely distributed in Europe, the Dragon 32/64 computers are very close cousins to it. While it supports a 256x192 mode, it seems to be strictly black and white. Compare the game "The Vortex Factor" for both systems.