In Organic pigments, the molecules are made of carbon atoms along with hydrogen, nitrogen or oxygen atoms. Organic pigments are further divided into two subgroups:
Natural Organic Pigments- This type of pigments are derived from animal products and plant products. The use of these pigments are rare due to their poor light fastness property.
Before the beginning of the modern era, the natural organic pigments were considered as an important part of the historical pigments. Earlier these are used for bodily ornaments, textile dyeing and cosmetics.
But, today a large number of the natural organic dyes have been replaced by the synthetic organic dyes. Therefore, today, these pigments are remembered by theirs quaint historical names. These pigments are being adopted by the modern commercial paint companies to lend romance in their traditional mixtures. And, the most important, these pigments are environment friendly.
Synthetic Organic Pigments- Synthetic Organic Pigments are carbon based and are often made from petroleum compounds. Most of the Synthetic Organic Pigments except Carbon Black are not stable and they will wear away at the time of using as a pigment.
Under intense pressure or heat, carbon base molecules are manufactured from petroleum, acids, and other chemicals and Synthetic Organic Pigments have been formulated from these molecules.
These two subgroups of Organic Pigments have been depicted in the following table:
Natural Organic Pigments
Miscellaneous: e.g Rose-Madder, BoneBlack, Carbon Black
Metal Complexes: e.g Transparent Yellow, New Gamboge
Miscellaneous: e.g Dioxazsine in Danthrone.
Why a large number of modern pigments are Synthetic Organic in nature?Carbon atoms have amazing flexibility and ability to form many different structures. That is why, the entire concept of organic chemistry mainly depends on carbon's atoms. Carbon atoms are able to form different combinations with other carbon atoms or atoms of other elements or with other compounds. This facilitates it to form almost limitless molecular variations. Out of these large number of carbon made molecules, intense color variations attribute will come in these synthetic organic pigments. Pigments which are formed out of these molecules, are the least toxic and economically beneficial.
AZO Pigments along with other organic pigments are derived from water soluble dyes.
Synthetic Organic Pigments are mainly derived from some selective elements atoms. These are as follows:
Chromophores are responsible for the color creation phenomena of the pigment's molecules. Chromophore is a pair or group of atoms. This pair creates a complex and dynamic clouding of the electrons within the respective electron shells in single atom or more then one atoms.