Masterbatches for polymers mass colouring are concentrates that transform thermoplastic and thermoset polymers from colourless and opaque materials to brilliant and coloured. The craft of polymer colouring is not only a matter of knowing the basics of the colours perception optical phenomena, but also understanding the reactions that pigments and dyes can have with base resin, mineral fillers and additives as well as the material final application and the processes undertaken. There are soluble colorant substances (dyes) and insoluble substances (pigments) that can be organic or inorganic, natural or synthetic. Combinations of these types of ingredients are contained in the modern masterbatches along with other non-colouring additives. It is through this complexity that it is possible to develop strength, depth and resistance to colours.