Specular gloss is the attribute next to color that is most often used in the evalua(,ion of the appearance of obj ect s. For 10 years t he American Society for T estin g N[a(,erials has used a method of test for the 60 0 specular gloss of pain t fini shes based on research done at this Bureau. The ASTM method prescribes the illuminator and receiver apertu res that are to be used. However, in order to determine the uncertain ties involved in the calibration of gloss standards, the rate of change of gloss reading with change of aperture was investigated throughout the gloss scale. Thi s was done by modifying an existing goniophotometer so that it became in effect a versatile glossmeter with provis ion for accuratcly controllin g all of the known geometrical vari ables involved. Data obtained on the variation of gloss readin g with aperture show that standards with widely different distr ibutions of re flected ligh t can be used to check t he adjustment of glossmeters and the conformance of thei r apertures to ASTM specifications in the in creasingly importan t medium-to highglos range. The problem of obtaining the d ir-ru e correction, which in vol ves sou ree polari zation and depart ure of the specimen from a pe rfect diffuso r, has been investigated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.