7
The Lighting Handbook
Relative spectral perception brightness and melanopic effect
Wavelength [nm]
Effect percentage
460 500
380 420 540 580 620 660 700 740 780
100
80
60
40
20
0
What does the human eye see?
λ
Wavelength [nm]
Night
V'( )
λ
Day
V( )
λ
Smel( )
λ
Explanation the three curves:
V(λ) Perception brightness, daytime seeing with the cones
V'(λ) Night-time seeing with the rods
Smel(λ) Melatonin suppression with the photosensitive ganglion cells
