Fading of colours is a matter for the manufacturer. When colours cost so much already it is only reasonable to expect the best of ingredients, and for labeling to accurately reflect contents so the artist can make wise choices. Likewise the paint binders should be in the proper proportions and not be unnecessarily adulterated.

On the other hand commonsense should prevail when painting. Appropriate preparation of surfaces should be seen in Zen terms of the beauty and honour of necessary work. Not painting acrylic over oily surfaces, or painting fat over lean with oil paint are ways of respecting the integrity of materials that work so hard to reveal your ideas. Rather than masking creativity, sound practices enhance your efforts.