Black glass is used in widely referenced high-precision ASTM Method D 2805 and related hiding power test methods. After measuring the reflectance R0 of the dry film, a defined area is scraped from the glass and weighed to obtain the spreading rate or original wet film thickness. R∞ of the paint film is obtained from a separate test application. The hiding power is then calculated from the appropriate Kubelka-Munk equations found in the ASTM method.
Black glass panels are used in U.S. Federal Test Method 141-4122 and CGSB Method 1-GP-71-14.7 for measuring hiding power. The latter method also provides for direct wet film thickness measurements using a Pfund or Inter-chemical type of wet film thickness gage, as described in ASTM Method D 1212.
These methods depend on the unique hardness and levelness characteristics of glass substrates. Although visually not as opaque as true Carrara Glass, Leneta Black Glass has a Y-reflectance of less than 1%, making it an adequate substitute for Carrara Glass.