In industrial colorimetry of QA non-luminous materials, assumptions are made that light reflected from or transmitted through a surface is relatively uniform, with only diffuse and specular components. To promote inter-instrument agreement, the CIE geometries for collecting the reflected or transmitted signal of non-luminous materials are standardized into directional and diffuse sphere types.
BRDF measurement serves as more of a research tool when you want to precisely quantify the pattern of light reflecting from a sample surface, or the pattern of light being transmitted through a clear material. Typical materials would be coated surfaces, plastics, films and metals.
Another major application area for BRDF measurement is quantifying the illumination pattern from self luminous light sources such as LEDs and HID lamps; and luminaires such as automotive displays, and architectural lighting.
HunterLab does not make BSDF equipment but here are some further resources for equipment and measurement services: