This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Blackbody efficacy K.svg en Luminous efficacy of blackbody radiator within to Kelvins The plotted data are derived by integration of Planck function convolved via the CIE photopic luminosity function equivalent to the function of the CIE colormatching functions Data points are interpolated as cubic splines by gnuplot The luminous