| The old adage is that to see
better, you need more light. Well, yes and no. Our
ability to perceive in the dark does not solely
depend on huge amounts of light. What helps us
perceive is effective contrast allowing us to
quickly interpret what we are seeing.
Interpreting quickly is what is key.
As
example, a camouflaged marine lying against a
tree can be invisible in bright daylight because
he does not contrast with his environment. We see
him but we don't perceive him. A person wearing a
white and red polka-dotted shirt in the same
environment would stand right out. More contrast.
Unfortunately,
contrast is greatly diminished in the dark of
night. In addition, our night vision is not
sensitive to colors. Everything appears in shades
of greytone or black and white, further
decreasing contrast.
For
a given amount of light, our night vision
receptors are significantly more receptive to a
cooler color of white (higher temperature) than a
warmer white (lower temperature). Warm colors
muddy contrast. Cool colors sharpen it.
How
important is contrast relative to amount of
light? As example, consider a very strong light
(say 400 watts) of very warm color ie a yellowish
tint. Everything would be bathed in a strong
glow, but contrast would be quite low. Our
ability to quickly perceive in the dark would be
diminished.
The
good news is that a white light at 4000K
temperature or above markedly increases effective
contrast.
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