The Amiga had such tricks as well to display 4096 colors at the same time on screen while it could only display up to 32 specs wise. Not sure how they do it on PC, but there's probably a way to achieve it as well.
CGA's "Composite" mode contains output artifacts, a trait also found in other early microcomputer graphics like those of the Apple II or Atari 800; with careful use of dithering, CGA can be expanded to a larger effective gamut[0] although most games wouldn't be as ambitious as this demo. It's not as well-known or used as the 4-color modes because it wasn't supported by later PC graphics adapters, nor was it in the spec of the standard monitors of the era. You can see this system struggle to reproduce the demo's intended look: [1]
You could either set any pixel color to any of 16 palette entries OR hold red & green from left side pixel, modify blue, hold red & blue, modify green, etc.
You could also change those 16 colors for every scanline (horizontal line).
Overall there was a lot of control, but software such as Deluxe Paint did not support full possibilities of HAM mode.
Comments
The Amiga had such tricks as well to display 4096 colors at the same time on screen while it could only display up to 32 specs wise. Not sure how they do it on PC, but there's probably a way to achieve it as well.
CGA's "Composite" mode contains output artifacts, a trait also found in other early microcomputer graphics like those of the Apple II or Atari 800; with careful use of dithering, CGA can be expanded to a larger effective gamut[0] although most games wouldn't be as ambitious as this demo. It's not as well-known or used as the 4-color modes because it wasn't supported by later PC graphics adapters, nor was it in the spec of the standard monitors of the era. You can see this system struggle to reproduce the demo's intended look: [1]
[0] Example: https://www.youtube.com/watch?v=TfVe9l77zLU
[1] https://www.youtube.com/watch?v=aibZKrXc8Nk
The 4096 color HAM mode was always part of the spec.
yes, it is, but it can only be used in very specific conditions (you cannot have the colors where you want all over the place), it's a pure hack.
You could either set any pixel color to any of 16 palette entries OR hold red & green from left side pixel, modify blue, hold red & blue, modify green, etc.
You could also change those 16 colors for every scanline (horizontal line).
Overall there was a lot of control, but software such as Deluxe Paint did not support full possibilities of HAM mode.
Oh and, btw, EHB (extra halfbrite) mode has 64 colors. 32 colors palette + second 32 colors with brightness halved. http://en.wikipedia.org/wiki/Amiga_Halfbrite_mode