Absolute or relative spectral measurements as a function of incident angle that meet or exceed the requirements of ASTM E308 and E903 are available. The instrument is a Perkin Elmer Lambda 950 Spectrophotometer, equipped with specially designed integrating spheres. Data for UV-VIS-NIR measurements include a report and one normalization (e.g., solar transmittance or reflectance, color, chromaticity, etc.).