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. Author manuscript; available in PMC: 2018 Aug 1.
Published in final edited form as: Physiol Behav. 2017 May 1;177:221–229. doi: 10.1016/j.physbeh.2017.05.002

Table 1.

Spectral characteristics of the light sources studied.

Radiometric and Photometric Values (380–780 nm inclusive) Retinal Photopigment Weighted Illuminances (α-opic lux)47
Photon Flux (photons/cm2/s) Irradiance (μW/cm2) Photopic Illuminance (lux) S Cone Melanopsin ipRGC Rod M Cone L Cone
FL (Experimental) 4.29 × 1013 14.82 49.37 17.18 31.18 35.35 43.79 48.82
C-LED (Experimental) 3.93 × 1013 13.26 47.65 6.73 18.59 24.35 36.82 48.12
FL (Dim light) 1.30 × 1012 0.46 1.45 0.63 1.01 1.13 1.32 1.42
FL (Ambient) 1.81 × 1014 64.71 214.77 136.49 147.22 168.00 194.16 208.56

Fluorescent (FL) and circadian-sensitive LED (C-LED) lights were measured 91 cm from the lamp, at 137 cm from the ground in the vertical plane, oriented directly to the center of the lamp. Overhead fluorescent lamps used to generate ambient and dim lighting conditions were measured at a height of 187 cm from the ground in the horizontal plane. Refer to text for lamp details.