Richard Clark wrote:
"The unintended consequence of this (exposure to white light) is that it
suppresses the eye`s ability to perceive red light at night (why you see
them (red lights) used in dark rooms and WWII movies--..)"
I was in WW-2 and confirm that aboard my ship our chartroom (the
compartment with an opening tp tje outside) indeed was illuminated with
red lamps so that we would not be blind when we stepped outside. We were
told that we used our cones in the daytime and our rods at night. How
could I ever have remembered that?
From Lincoln`s Reference: Glare is said to reduce the ability to see,
and hastens fatigue. Glare is wasted since it lowers the effectiveness
of useful light. Glare is high light energy over a measurable period of
time from above normal angles of vision (30 to 90-degrees above the
vertical). I think this means you don`t want a bright light shining in
your eyes. It`s glaring and impairs vision for awhile.
I wasn`t a signalman but I noticed our signaling light was fitted at
night with a red filter called the "Nan-gear". Our phonetic alphabet in
those days went: able, baker, charlie, dog---nancy. I suppose Nan was
short for nighttime gear. I speculate it was hoped that the enemy would
step out of white lighted quarters and not notice our red signal beams.
So much for red lights and glare.
It probably wouldn`t work, but you might say to the policeman: I didn`t
see the red light. The white glare desensitized my eyes!
Best regards, Richard Harrison, KB5WZI
|