Now I am confused with this thread...
Surely the difference in heat is what is detected by an IR sensor.
Military applications (the only ones that I am familiar with) are
based on being able, for instance, to detect where vehicles are
hiding in woods. Depending on the time of day, and crossover etc...,
you can find vehicles that have been running their engines.
Likewise, an IR seeker on a missile follows a heat source because it
emits radiation in a certain range of wavelengths.
The Forward Looking Infrared (FLIR) sensor in the aircraft that I
flew could show you differences in reflected heat certainly, but the
exhausts of a pair of turbofans in a Tornado was not reflected heat.
I have only partly followed this thread (wondering how long the
fading "personal freedom" altercation would last, and whether it
would end with apologies or recrimination), so forgive me if I have
jumped back a step in the discussion.
Finally, I am assuming that IR film acts in a fashion similar to the
real-time sensors.
Chris
>I'd like to respectfully disagree, Doris. I believe such effects are
due entirely to *reflected* IR. I'd challenge you to take such photos
in complete darkness.
Infrared film does not detect the temperature of an object. It only records
the reflected infrared wavelength light in the range of 600-900nm, which has
nothing to do with temperature. There is a false color Kodak E6 infrared
film that is pretty cool. It's used for forest and crop surveys, since the
amount or quality of IR light changes with the health of the plant. It's
also used for art. There are a couple of IF B&W films also....
Be seeing you.
Dirk Wright
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