quarternary color mixing wrong

Plum, a dark reddish purple, is purple+red or purple+russet. Sage, a greyish green, is green+slate or green+blue. Buff, a moderate orange-yellow to yellowish brown, is orange+yellow or orange+olive. Note: Slate+russet = yellowish-to-dun purple; olive+slate=brownish green; russet+olive=ashen orange or deep burnt orange. Further mixing of tertiary colors always gives varying degrees of muddy brown to gray, taupe, or dun.

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