For tinting: After the grinding and finalization, the pastes are used for the final fine adjustment of the color, i.e. for nuancing. In this case, only a small percentage of the pastes are used. The individual components of the pigment concentrates (especially the grinding resin) then have virtually no obvious influence on the quality of the coating that has been tinted.
For production: A coating can also be made up entirely of a blend of pastes and then let down with the desired binder (as a clear coating or white coating). Greater quantities of pigment pastes are required for this. As the pastes then have a significantly greater influence on the coating quality, the requirements on the quality of the pigment concentrates are also considerably greater.
While it has always been conventional practice to use tinting pastes, it is only in the recent past that the option of making coatings made entirely from paste blends has been more broadly received. Pastes are then used for production if the coating application is comparatively small, but a broad spectrum of colors and binder systems needs to be covered (typically, for example, with industrial coatings).
Manufacturing from pastes is quicker than manufacturing using a millbase and the coating manufacturer can respond more flexibly to customer requirements. Pigment concentrates can also then be used in automated coating production, as this is only possible if pumpable pastes are used instead of powdered pigments.
There are generally two possible variants. You can design a series of pigment pastes which are to be used only for one unique coating system. The actual coating binder is then also used as the grinding resin for the pastes. Such pastes can be optimally used in the coating system.
The other option is to develop a “universal” series of pastes which is compatible with most binders and can therefore be used to produce very different coating qualities. Of course, “universal pastes” will not necessarily be ideal for each type of coating binder. Compromises are inevitable in such cases.