A pigment is one of the elements in the composition of paint, together with resins, solvents and additives. Commonly, pigments can be found in the form of powders with small granularity factor and are responsible for providing the paint its actual color. Pigments are introduced into paint after previously being combined with a resin and as part of a solvent solution.
Pigments fall into two categories, based on the purpose in the composition of paint – prime pigments and extender pigments. Prime pigments are the pigments which provide the actual coloration of paint and are usually quite expensive, especially if produced in agreement with best quality standards. Higher quality means the right granularity, an even color shade and a need to apply the paint maximum two times to obtain the results wanted.
The size and shape – or the granularity – of particles composing pigments is very important and has a great impact on the colors obtained. Too fine a granularity of pigments will result in paints with a small dispersion factor, meaning that one will have to apply the paint several times to obtain the desired coverage. This happens because fine pigment particles become electrically charged and repel each other like magnets.
Extender pigments have the role to complete or “fill up” the painting. They are extremely important in the composition of paint, as they influence the overall characteristics of the paint, such as color intensity, the hiding power (or the ability of the paint to conceal any previous coating), the persistence over time of the color and the resistance to cleaning.
Both prime and extender pigments are of organic or inorganic origin. Pigments with organic source are usually brighter in color and have a higher coloring strength compared to their inorganic counterparts. Also, organic pigments are considered safer to use and more environmental friendly.
Inorganic pigments, on the other hand, have a very good resistance to light, which is an extremely important quality. Until recently, low light resistance has been an issue with all organic pigments, together with production-associated costs. This made organic pigments virtually too expensive for use on industrial scale. Recent advancements in the paint production industry have helped overcoming these drawbacks.