If a watercolour mixture looks lighter after drying than when wet, what should the artist do?

Correct answer: Dry a test sample before judging the final value

The governing concept is the drying shift of transparent watercolour. Wet paint can look darker or more saturated because water temporarily changes how light passes through the pigment; after evaporation, the dried wash may appear lighter. The reliable method is to paint and dry a small test sample, then judge its final value before working on the artwork. Adding black every time can muddy the colour and is not a controlled solution.