Potential use of secondary dying to create checked patterns? Could be used to create patterning without extra cost.
Tiny wee bitty red. Expensive stuff, but doesn't it add the cheer, no?
Put a tiny wee bitty red next to a larger area of green and it brings it right up. Something to do with the biology of the eye and the way it perceives red and green. I think it uses the same bits of the eye for both.