It’s always good to have a firm mental picture of one’s (artistic) process, as to not get bogged down by the details. I’ve updated the C64 multicolor illustration I did yesterday, and separated it into 4 “colors”:
@renevanbelzen Alas, I got it wrong. Yes, there's a background color and 1000 character spaces of color memory, but there are, per character space two more colors to pick from, each stored in the lower and higher four bits of an 8-bit character code. There's an additional 1000 character spaces to store those. For multicolor character mode, yes there are three background colors, and then so more restrictions on the colors that can be used.