Why may a problem occur in the final artwork if the artist judges a wet mixture only on the palette?

Correct answer: The colour may look different on the surface and after drying

The governing concept is that a pigment mixture must be evaluated on its intended support and, when relevant, after drying. Watercolour, poster colour, and other media can change in lightness, transparency, or apparent saturation as water or binder dries. The paper’s colour and texture also affect perception. Therefore a palette view alone can mislead the artist; a test swatch on the actual surface is safer. The palette does not make colour white, and the other distractors describe no general rule.