luminous flux/power

luminous flux/power (In French flux lumineux) product of luminous intensity and radiated solid angle [candela times steradian, cd·sr]; the SI unit is lumen [lm]; the weakening of the luminous flux through absorption is measured as degree of remission and, as a spectral degree of remission, forms the basis for all colorimetric parameters over the entire visible wavelength range. With video projectors, the illuminance reaching a surface [lux times square meter, lx·m²] at a defined distance is designated “ANSI lumen” (IEC DIN EN 61947-1).