To reduce the cost of paint, fillers are added. If used too much it can weaken the paint. Alumina, magnesia, barite, charcoal, etc are examples of filler.

Soapy patches appear on the painted surface due to chemical reaction of alkalis. This defect is called Saponification.

Cobalt is not a base instead it is a drier. It is used to absorb oxygen from surroundings and harden the paints.

Emulsion paints have polystrene as a base. Emulsion paints are durable and can retain colour for too long. They dry within 15 minutes and hard dry within 2 hours.