If a colour consistently appears lighter after drying, what should be done for accurate mixing?

Correct answer: Keep the wet mixture slightly darker or more saturated based on a dry sample

The governing concept is calibration for a drying shift. If the medium repeatedly dries lighter, the wet mixture should be adjusted slightly darker or more saturated after comparing a test sample with its dry result. This uses observed evidence rather than guessing. More water or white would generally make the final colour lighter, and stopping tests removes quality control. Thus option A is correct.