What effect will a small amount of blue have on an orange mixture of red and yellow?

Correct answer: Orange will lose saturation

The governing concept is complementary colour mixing. Orange and blue are opposite, or complementary, colours on the colour wheel. Adding a small quantity of blue introduces a contrasting pigment that absorbs part of the orange visual effect, so the orange becomes less pure, duller, and lower in saturation. It does not normally become green or pure yellow; a larger quantity would make the mixture increasingly muddy.