PRO has discovered that light output based on "wattage" ratings of compact fluorescent lamps varies widely. A large variety of factors impact the output and "wattage" is not an accurate reflection of the lamp output.

Based on this, PROMASTER has adopted the use of a Photo Luminance Factor which more accurately reflects the light output of the PROMASTER Compact Fluorescent Photo Lamps in studio use. Each lamp in the PROMASTER line has been evaluated based on a single lamp in a 10" photo reflector measured at 10 feet.