Note: Larger version of the above shot HERE.
This is the 855 color square wall (570 different colors) in Imgur user str3ck's bedroom that he spent 400-450 hours painting over the course of three years entirely by hand without taping or masking the surface in any way and MIXING EACH COLOR INDIVIDUALLY USING ONLY BLACK, WHITE, YELLOW, CYAN AND MAGENTA. My God, and I thought I was a masochist.
This is a wall in my bedroom. When I bought my house I had to repaint everything since the previous owners where clearly not painters. Anyway after painting the room white I knew I needed an accent wall but couldn't decide on the color. So I made the joke about painting it every color.
570 different colors. All hand mixed using a syringe so I can recreate them if i ever need to. The only store bought colors were Black, White, Yellow, Cyan, and Magenta.
Str3ck says he had to start the entire wall over from scratch twice due to mistakes, after the first of which I would have just said f**k it and burnt the house down and collected the insurance money. When reached for comment about how he's enjoying the wall now that it's complete, Str3ck had already moved and the new owners had painted it black.
Keep going for a couple closeups.
Thanks to Tam, who agrees the best wall color is the Behr brand paint Positive Energy green (S370-1) I just painted my bathroom. It's so relaxing I can fall asleep peeing standing up.