Black Carrara Glass Paint Panels are used in U.S. Federal Test Method 141-4122 and CGSB Method 1-GP-71-14.7 for measuring hiding power. In both methods the dry film thickness is measured by means of a micrometer. The latter method also provides for direct wet film thickness measurements using a Pfund or Interchemical type of wet film thickness gage, as described in ASTM D 1212. These methods depend on the unique hardness and levelness characteristics of glass substrates.
Black glass is used in widely referenced high-precision ASTM Method D 2805, and related hiding power test methods. After measuring the reflectance Ro of the dry film, defined area A is scraped from the glass and weighed to obtain M, which is inserted along with A into the equation below to obtain the spreading rate or original wet film thickness. R of the paint is obtained from a separate test application. The hiding power is then calculated from the appropriate Kubelka-Munk equations.