W. CONSHOHOCKEN, PA - Manufacturers and developers of architectural coatings will be the primary users of a new ASTM International standard, ASTM D 7786, Test Method for Determining Enamel Holdout. The standard was developed by Subcommittee D01.42 on Architectural Coatings, part of ASTM International Committee D01 on Paint and Related Coatings, Materials and Applications. 

Keith Alderfer, Associate Scientist, The Dow Chemical Co., and a member of D01.42, said that enamel holdout is an important attribute of an architectural primer. "The enamel holdout characteristic of a primer can have a significant impact on the appearance of the finished painted system, especially if that system is intended to have a semigloss or glossy finish," said Alderfer. "Semigloss topcoats over primers with poor enamel holdout characteristics or unprimed porous substrates can result in lower gloss than is intended from the final coating." 

While ASTM D 7786 is now complete, Alderfer said that interested participants are invited to join in inter-laboratory testing on the standard that is planned to begin this year.  

For additional information or to purchase the standard, visit www.astm.org.