If transparent blue is layered over transparent red, what determines the quality of the visible violet?

Correct answer: Transparency and pigment bias of the layers

The governing concept is transparent layering, or glazing: light passes through the upper blue film, reaches the red layer, and returns to the viewer. The violet will look clearer when both layers are sufficiently transparent and their pigment biases are cleanly blue and red. Muddy or yellowish impurities absorb competing wavelengths and dull the mixture. Brush length, paper name, and artwork title do not determine the resulting hue quality, so option A is correct.