Why is it important to record different proportions in a colour-mixing exercise?

Correct answer: To reproduce the same colour result later

The governing concept is controlled colour mixing and reproducibility. A colour depends not only on which pigments are used but also on their relative amounts; for example, changing a 1:1 mixture to 2:1 changes its hue, value, or intensity. Recording the proportions creates a practical recipe that can be repeated, compared, or adjusted later. It does not affect paper value, brush length, or colour names. Therefore option A is correct.