We measure TAPPI (or GE) brightness using either a Technidyne S-4 Brightmeter, or a Technidyne S-5 Brightmeter; both of which measure brightness in accordance with TAPPI test method T-452. The S-4 only measures directional brightness, while the S-5 measures both directional brightness and shade.
For measuring diffuse brightness and shade, we have both an L&W Elrepho 070 spectrophotometer and a Hunter ColorQuest XE spectrophotometer. Both of these instruments measure brightness and shade using diffuse lighting and an integrating sphere. Measurements can be performed with either “C” or “D65” illuminates.