Compounds that are completely soluble in the final product. On the basis of the medium in which they are soluble, they can be divided into :
Water soluble dyes namely colourings that are soluble in water
Solvent dyes soluble in solvents (alcohol, acetone etc), oil, wax and grease.
The colourings all have a good level of overall lightfastness and a high level of brightness.
These are insoluble compounds that disperse uniformly into the final product (that can be water, solvents, powder-based compounds, oil, grease, wax, resins, etc.). Depending on their origins, they are divided into Organic and Inorganic pigments. Pigments are marked by a high lightfastness.
When water-soluble colourings are precipitated on a substrate of aluminium hydrate, insoluble products having pigment-like properties are formed. These products are able disperse into the application medium. If compared to the water-soluble colourings from which they originate, lacquers have a better resistance to light but must be used within a pH interval between 4 and 7.
In addition to their general fastness, the distinguishing feature of colourings, pigments and lacquers is their colouring power: that is, their capacity to transfer the colour to the medium by which they are applied. In colourings, colouring power is linked to the quantity of product, but with pigments and lacquers it depends on the size of the particles: the more finely they are ground, the higher the colouring power and the smaller the quantity of product to be used.