The two important colorant sources are the dyes and pigments. However, there lies some difference in the features, manner of use, benefits and the sore points of each of them though quite often the terms, pigment, dye, colorant, dyestuff, paint, colour are incorrectly used interchangeably.
Colorants come from organic and inorganic sources and dyes constitute a large percentage of the organic colorants while the pigments come largely from the inorganic sources. Naturally sourced pigments are obtained from animals, vegetables and minerals sources; however, majorly pigments comprise of inorganic oxides and salts like chromium and iron oxides that get diffused in powder form in the medium of application. The coloring properties of the diffusion are determined by the form and size of the pigment particle. The dyes are divided into natural dyes and synthetic wherein the natural sources of dyes are the same as those of pigments while synthetic dyes are petroleum compound based.
Dyes and pigments both are equally important to humans for providing colour to all type of items but the major difference between the two lies in their basic manner of imparting colour. In case of dyes, colour is diffused at the molecular level as they are soluble in the organic solvent or water whereas in pigments the colour is diffused as particles because they are insoluble in either type of the liquid medium. Additional compounds are required for attaching the pigment particles to the substrate. For example, pigments for paint require addition of polymer in paint for diffusion.
The vibrancy of colour of the dyes is dependent on its chromophore molecule's electronic properties. Colorants from dyes impart greater brilliance and show greater colour strength besides being simpler to process. Among the dyes, basic dyes are more known for their vibrancy and brightness and compatibility with anionic and synthetic materials. All basic dyes manufacturers in India will confirm their suitability for coloring cationic, synthetic items like acrylics. However, dyes as colorants exhibit low durability, solvent and heat stability and high levels of migration and acid red being one of them is no different.
On the other hand, pigment colorants are more durable, solvent and heat stable besides being migration and lightfast. But their cons include low colour strength and brilliance. Due to the starkly different features of dyes and pigments many efforts were made to enhance the properties of each colorant class. This led to the development of a new colorant class called as the Nanocolorants.
This class strives to combine the good processability and superior chromatic features of dyestuffs and better durability of organic pigments. Combining the advantages of both the colorants, Nanocolorants have emerged a better alternative and has demonstrated superior features proving highly useful in several applications such as preparing aqueous ink-jet inks, high-performance colour resistant polymer coloration, electro-photographic toners amongst others.
In any case, notwithstanding the features, dyes and pigments are indispensable elements for helping us to lead a color filled life.