All paints consist of at least one pigment and binder. The quality of those assigns the quality of paints.
Pigments can be natural and synthetic. Natural pigments can be divided into organic and inorganic. Inorganic or mineral pigments come from earth and rocks.
Pigments have their own marks that you can find on a paint label. The first letter stands for nature of colour: N means natural, while P means pigment. For example, NR is Natural Red. The second letter stands for colour:
PB = Pigment Blue
PBk = Pigment Black
PBr = Pigment Brown
PG = Pigment Green
PM = Pigment Metal
PO = Pigment Orange
PR = Pigment Red
PV = Pigment Violet
PW = Pigment White
PY = Pigment Yellow
This mark is accompanied by CI (Color Index) and Pigment Name.
Generally speaking, paints based on one single pigment are better and always preferred due to purer tones and more predictable results in mixing; therefore, manufacturers seek ways to produce mono-pigment paints. Most of the professional grade paints are based on single pigment. Usually student grade yellow, reds, and blue colour consist of more than one pigment that decreases quality.