When a child combines the yellow and blue crayon colors in her drawing, the resulting color is green. Why is this so?

Question

Quizplus · Accepted Answer

When yellow and blue pigments are mixed, the mixture absorbs the wavelengths corresponding to each of those colors. The colors that are not absorbed by the pigments are reflected, and in this case, the reflected color appears green to the human eye. This is due to the subtractive color mixing process, where pigments absorb certain wavelengths of light and reflect others. The colors that are reflected combine to form the color perceived by the observer, which in this case is green.  When yellow and blue crayon are combined, yellow absorbs blue and blue absorbs yellow, leaving unabsorbed only the wavelengths that look green. Both the yellow and blue crayons allow some wavelengths that look green to escape; these are the wavelengths that are not absorbed.

When a Child Combines the Yellow and Blue Crayon Colors