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A Mixture Of Barium Sulfate And White Paint Is A Low-Cost Substitute Reflectance Standard For Spectralon®, Nick Knighton, Bruce Bugbee

Techniques and Instruments

Barium sulfate is a white powder that has historically been used as a reference standard (Weidner and Hsia, 1981). It may be a less expensive alternative to higher priced white standards that use sintered PTFE (polytetrafluoroethylene; Spectralon®, Labsphere, Inc., North Sutton, NH). A 500 g bottle of BaSO4 costs $25, whereas reflectance standard made of Spectralon® and with a 99% reflectance factor costs $385. However, pure barium sulfate dries to a powder and easily rubs off surfaces. We sought to increase the durability of barium sulfate by mixing it with untinted white latex paint. Reflectance and durability of different ratios …