The solids of a paint are known as pigments. Bases being solids in nature are also known as pigments. It is the principal ingredient in a paint and performs the following functions:

1. It gives the body to the paint.
2. It gives opacity and covering power to the paint. Thus, the base hides the surface to be painted.
3. It makes the film of paint harden and more resistant to abrasion.
4. It prevents the formation of shrinkage cracks, which are usually formed on drying of a paint.

The bases commonly used as principal constituents, forming body of different paints, are briefly described below:

(i) White Lead: This base or pigment is the cheapest and most extensively used for ordinary painting works. It forms the base for lead paints. It has a great covering power, protective qualities and workability. It is most suitable for painting wood surfaces. It is not recommended for iron surfaces as it does not protect iron from rusting. This should also not be used for delicate work as it turns black when exposed to atmosphere contained with sulphur vapours.

(ii) Red Lead: This is base is an oxide of lead and it forms the base for lead paints. It has got excellent properties of rust prevention, toughness and durability. It is generally used for painting iron surfaces and as priming coat for wooden surfaces.

(iii) Zinc White (Zinc Oxide and Zinc Sulphate): This is an oxide of zinc and it forms the base for all the zinc paints. It is non-poisonous, transparent, smooth and unaffected by the sulphur fumes. It has high cost, less durability and poor workability.

(iv) Iron oxide: This is an oxide of iron, and it forms the base for all iron paints. The tints of paint obtained vary from yellowish brown to black. It is cheap, durable and protects the iron surfaces against rusting. It is used as priming coat for iron surfaces.

(v) Titanium White or Titanium Dioxide: It is an oxide of titanium of brilliant whiteness. It is very fine pigment which is non-poisonous and unaffected by heat and acids. This base possesses high oil absorption, great elasticity and very high covering power (nearly twice the covering power of white lead). It is generally used as an under coat to enamel or organic coatings.

(vi) Aluminium Powder: This forms the body of aluminium paints. It checks the cracking and warping defects of wood. It is generally used as a priming coat to new wood work.

(vii) Lithopone: It is a white substance obtained by mixing equal quantities of zinc sulphide solution and barium sulphate solution in the full form of precipitate. It is cheap and has a good covering power. It is generally used for interior work as under coat. It is also used in cheap enamels.