Currently, photometric standards are calibrated only at CIE-recommended geometries. A need exists for calibrating at many combinations of illumination and viewing angles. The common practice is to assume BaSO4 is lambertian although its non-Iambertian behavior is well-known. Accordingly, a study was undertaken to develop a standard for this type of metrology. Two diffuse materials, BaSO4 and PTFE, were characterized goniospectrophotometrically. PTFE, when pressed to a density of 1.55g/cc against a lapping film, exhibited properties lending itself as a transfer standard. Bidirectional absolute spectral reflectance factors at 60 combinations of illumination and viewing angles in a single plane were measured. Neither material was found to be lambertian and both polarized the reflected radiation. The PTFE standard had greater spectral non-selectivity and could be prepared repeatably.
Library of Congress Subject Headings
Spectrophotometry--Technique--Standards; Angles (Geometry)--Measurement--Technique--Standards; Reflectance; Colorimetry--Standards
Mark D. Fairchild
Daoust, Denis J. O., "Development of a photometric primary transfer standard for reflectance goniospectrophotometry" (1987). Thesis. Rochester Institute of Technology. Accessed from
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