@article{Fairchild1990_0,<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Abstract = {Currently, spectrophotometric standard reference materials are calibrated only using the CIE recommended illumination and viewing geometries. A need exists for standards that have been calibrated at many other combinations of illumination and viewing angles. The common practice has been to assume that a primary transfer standard such as BaSO4 is Lambertian even though its non-Lambertian behavior is well documented. This study was undertaken to develop a practical standard for this type of metrology. Two diffuse materials, BaSO4 and PTFE, were characterized goniospectrophotometrically. Bidirectional absolute spectral reflectance factors were determined for 60 combinations of illumination and view angles in a single plane. Neither material was found to be Lambertian and both failed to completely depolarize reflected radiation. The results were modeled using principal components analysis. The resulting model allows the determination of bidirectional spectral reflectances factors with a minimum effort. PTFE powder can be prepared repeatably with no significant effect on the measured reflectance properties, thus indicating that it would be a suitable primary transfer standard for goniospectrophotometry.},<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Author = {Mark D. Fairchild and Denis J.  Daoust and Jason  Peterson and Roy S.  Berns},<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Journal = {Color Research and Application},<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Keywords = {goniophotometer; absolute reflectance},<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Month = {},<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Number = {},<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Pages = {311--320},<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Title = {Absolute reflectance factor calibration for goniospectrophotometry},<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Url = {},<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Volume = {15},<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Year = {1990}