Abstract: An improved thermosetting acrylic enamel containing a film-forming polymer blend of(1) an acrylic polymer containing reactive carboxyl and hydroxyl groups,(2) cellulose acetate butyrate having a 1-6 second viscosity, and(3) a melamine formaldehyde resin at least partially alkylated with an aliphatic monohydric alcohol;The improvement used in combination with the above comprises 0.1-5% by weight, based on the weight of the polymer blend, of iron pyrophosphate powder; this enamel forms a high quality finish on automobiles and trucks and the iron pyrophosphate provides improved gloss retention, and improved blister and darkening resistance under high temperature and humidity conditions.