This is a frequently asked question, and it has a complex answer. Both composition and performance specifications can be critical and applied together. Composition specifications have been successfully used where production of an end-user-developed coating is desired, as in some military applications. However, over time, technology may make the coating specification obsolete. Performance specifications have been useful for companies that know what they need the coating to do but don't know which technology will work.
Compositional specifications can, as one part of the specifications list, be important for almost all coatings. For example: the amount of resin to pigment, and the total solids, can be very important. If there is not enough resin, the paint may fail cohesively or adhesively. Setting a minimum level for the binder can aid in obtaining quality coatings, and a minimum level of hiding pigment can aid in getting paint with adequate hide. However, pigment content is usually covered by performance specifications such as hide and color.