DIYbanter - View Single Post - Strange problem with low energy light bulb

Lostgallifreyan

(Don Klipstein) wrote in
:

1. The spectrum is richer in wavelengths favorable to scotopic
vision, which lacks ability to see color. Higher color temperature
favors things looking grayish when illumination level is down to
several lux or less.

2. More light of wavelengths favorable to scotopic vision can make
your eye's pupil smaller than otherwise for a given illumination
level. 100 lux at 5000 K can make your pupil smaller than 100 lux at
3000 K. (The lux and other photometric units are defined in terms of
photopic vision and not scotopic vision.) That can make things appear
dimmer. This can also have an effect on color vision if illumination
level is down to a few lux or less, by depriving the color-sensing
cones of light.

3. Reds look darker at higher color temperature, and can "drop out to
black" when color temperature is high and illumination level is low
enough to start making photopic vision marginal.

All true, but balanced perfectly, whatever the explanations might be, by
the sense of utter dinginess that a dim incandescent or red-heavy CFL
makes. Whether a spectrum favours photopic or scotopic vision, it looks
dire if we have to make an effort to perceive colour and space with it. I
think that the drain on our effort is partly what causes drear. That and a
lack of contrast, which might account for the feeling even in high daylight
illumination. I like LED's better than CFL's because they allow more
natural contrasts, if shone on white paint they are like sky, if direct,
they are like sunlight (though lacking in colour balance). CFL's don't
manage either convincingly at all, I find.