Coloring pigments in concrete: Remedies for fluctuations in raw materials and concrete recipes?

The customer places high demands on the product concrete. One of these is without doubt the look of the concrete surface. The expectations placed on colored concrete or fair-faced concrete surfaces are especially high. Solutions for all technically possible parameters and for prevention of avoidable mistakes have long since been implemented by most concrete manufacturers. But market requirements, customer wishes, and tender texts nevertheless continue not to correlate with actual product qualities. Why is that so?