Realization of the candela from a partial filtering V (lambda) detector traceable to a cryogenic radiometer

This paper describes the approach used to realize the candela from illuminance measurements made with a large-area, partial-filtering photometer. The methods followed to determine the absolute responsivity at 555 nm, traceable to an absolute cryogenic radiometer, and to measure the relative spectral responsivity are discussed, including the uncertainty values of the measured quantities. Finally, preliminary results obtained on comparing the photometer measurements with the previous luminous intensity scale are presented.