Pigments and their classification

Introduction

Pigment is derived from word “pigmentum” means coloring matter.

“Pigments are organic and inorganic materials which are practically insoluble in medium in which they are incorporated”

Pigments are used almost 30,000 years ago. The first synthetic pigment was Prussian blue which was synthesized in 1704. About 2000 BC natural ocher was burnt sometime in mixture with manganese ore to produce red, violet and black pigments for pottery.

Classification of pigments

Pigments are classified into organic and inorganic pigments.

Organic pigments are based on carbon chains and carbon rings. However, they can also contain metallic (inorganic) elements that help stabilize the properties of the organic component. 

Inorganic pigments, chemical compounds not based on carbon, are usually metallic salts precipitated from solutions. 

Organic Pigments are classifying into following:

Azo pigments

Polycyclic pigments

Anthraquinone pigments

Dioxazine pigments

Triayl carbonium pigments

Quinophthalone pigments

Inorganic pigments are classified into following:

White pigments

Black pigments

Special pigments

Color pigments

Properties of organic pigmentsThe properties of organic pigments differ from inorganic pigments. The properties of organic

pigments are as follow:

High color strength

Give bright shades

High light fastness

Good weather fastness

Properties of inorganic pigments Weak color strength

Dull shades

Low light fastness

Low weather fastness

Applications of pigments

There are many applications of pigments. Pigments are used for coloring of leather, building

materials, paper, floor covering and ceramic glazes.

Pigments are used for coloring paint, ink, plastic, fabric, cosmetics, food and other materials.

Most pigments used in manufacturing and the visual arts are dry colorants, usually ground into a

fine powder. This powder is added to a vehicle (or binder), a relatively neutral or colorless

material that suspends the pigment and gives the paint its adhesion.