Apparently, if you use a composite monitor or TV set on a CoCo 3, you can just put bytes on the 640x192x4 color video mode and they create artifact color. You can get over 200 artifact colors that way with no special tricks other than a palette translation to know what byte value is what color.
Yes, this has been known for awhile (commercial programs like GrafXpres from Sundog used similar back in the early 1990’s).
What I didn’t realize is that it was just an exciting mode using greyscale colors. I spent many years with a TV set on my CoCo 3. Wish I had realized this.
More than 256 colors are possible too. Palette changes, either full screen, or scan line with any of the non grey colors will bias the artifact colors.
I wonder what the upper limit is without page flipping? Still limited to … how many per scan line area?