Extenders
Extender pigments are added in order to reduce the cost of a paint formulation. They are also used to modify the flow (viscosity), sedimentation stability and film strength. Most extenders appear white and possess a refractive index similar to commonly used binders. Majority of them occur naturally and others can be produced synthetically. Aluminium silicate, magnesium silicate (talc), silica, calcium carbonate (synthetic and natural) and barium sulfate are some commonly used extender in paints and coatings.