A paint system is an operation in which different types and layers of paint or other coating materials are applied in a certain sequence. Each layer serves its own special purpose. The combination of these different types of coatings and paints ideally leads to the best solution possible to protect the base material (substrate) from corrosive and weathering environments.

Different paint systems are used depending on the base surface viz. Plastered wall, metal, wood etc and whether the surface is exterior or interior.

Paint systems are categorized by the number of layers that they have. Two, Three, four, five and six coat paint systems exist, and there are even higher number paint systems that are used. There are one and two coat, or duplex, paint systems that are used as well.

A paint system typically consists of a primer, an intermediate coat and a finish coat. A primer is the first coating in the system. It is applied directly to the base material. The primer is used to not only provide protection for the base material, but also to give the subsequent coatings an excellent surface to adhere to. The intermediate coating or coatings are used to provide thickness to the paint system. Typically, the thicker the coating requirement, the more intermediate coatings will be needed; however, this is not always true if the intermediate coating being used can achieve high thicknesses in a single application. The finish coating serves two purposes. It provides aesthetic appeal, if desired, to the overall paint system. Also, since it is the outermost layer, it is used to protect the paint system. It must protect it from abrasion, water, sunlight, and other conditions that are detrimental to the paint system