Any category of strongly colored substances used to color other materials is referred to as a pigment. Because they are insoluble, pigments are applied as finely powdered solid particles dissolved in a liquid rather than as solutions. Inks for printing, polymers, and oil- and water-based paints all use the same pigments in general. Organic and inorganic pigments both exist. Most inorganic pigments are more vibrant and durable than organic ones. Petrochemicals such as coal tars and others are used to make synthetic organic colors. Inorganic pigments can be created through very straightforward chemical processes or are found in nature as on earth.
White opaque pigments are an example of an inorganic pigment that is used to provide opacity and lighten other colors. Titanium dioxide is the class's most significant member. Paints can be made more affordable or have better qualities by adding white extender pigments. Particles of carbon are generally used to make black colors. For instance, printing inks are colored black using carbon black. Different cadmium compounds provide vivid yellows, oranges, and reds, while specific chromium compounds are employed to produce chrome yellows, oranges, and greens. The most popular blue pigments are iron, sometimes known as Prussian blue, and ultramarine blue, both of which are inorganic in nature.
Currently, aromatic hydrocarbons are used mostly in the synthesis of organic pigments. These are substances that have closed ring-like structures made of carbon atoms and hydrogen atoms. A nitrogen group is present in azo pigments, which make up the majority of the organic red, orange, and yellow pigments. Brilliant, potent blues and greens that are unusually colorfast for organic colors are produced by copper phthalocyanines. Some pigments, such as fluorescent ones, are only dyes that have undergone a chemical reaction to make them insoluble.