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Re : Red Lighting

  1. Feb 2, 2006 #1
    hi all,

    I am a Physics Learner and have a following question:

    Why do secret military installations like plane hangars etc lighted by 'RED' lamps?Also the CCC rooms have red lights.Isn't it ironic that red color is also used as traffic signal because it is visible for the farthest distance?

    Am I wrong somewhere...let me know
    Thanks in advance
  2. jcsd
  3. Feb 2, 2006 #2


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    Red is used at night because it doesn't spoil your night vision.
  4. Feb 2, 2006 #3
    Thats my point tooo....see if red is good for vision and also has high visibility,why is it used for military hangars etc where the purpose wud be to hide whtever is taking place...
    Checkout the attachment...
  5. Feb 2, 2006 #4
    Red has not, as you call it, high visibility. I believe green has the highest visibility.
  6. Feb 2, 2006 #5
    Re:Red Lighting

    I guess red color because of its inherant property of high wavalength n low frequency has high visibility.
    Ex : Tall bldgs,towers have red beacons because they have to have :rolleyes: maximum visiblity
  7. Feb 2, 2006 #6
    green has the highest visibility; astronomers use green-laser pens.

    It is correct that red is used because it doesn't spoil your night-adaption as much as other colours - astronomers use red-torches if they absolutely have to have light.
  8. Feb 2, 2006 #7


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    I don't see an attachment, but red lighting on top of buildings is an FAA requirement. If the military doesn't want you to see them, they simply turn their lights off. Navy ships, for example, burn the same running lights everyone else does, but go to great lengths to make sure those are the only lights visible on the ship at night. In combat, they either turn the running lights off or rig fake configurations to fool people into thinking they are something else.
    Last edited: Feb 2, 2006
  9. Feb 2, 2006 #8


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    Red is used because the rods in the eyes aren't as sensitive to it as other wavelengths, so we can remain dark-adapted better; this is only true for dim red light though. But, that's okay, because we also have a lot of red cones right in the center of the retina, so under dim lighting conditions, red provides us with the best visual acuity, short of dim white light. So, if you're attempting to remain dark-adapted while still being able to do detailed tasks, red works best. However, having worked a great deal under dim red lighting, I can say that the light levels that are low enough to not affect night vision are still not very easy to work in (to avoid detecting the light by the rods, the light needs to be <25 lux at eye level; that's what we use in all circadian biology experiments), and probably lower than are used by most people who would have any other reason to work under dim lighting conditions.

    Russ can correct me if I'm wrong, but when you're on a ship or other military installation, I don't think you'd have red lights (other than running lights or warning lights on the tops of buildings) any place that would be visible from outside. I think they are used when people on watch need to come inside and remain dark-adapted while checking charts or whatever they need to do, so when they return outside, they don't need to wait for their eyes to adjust again.
  10. Feb 2, 2006 #9


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    All the military bases I've been to, I saw no red lights. But the insides of some of the hangers were pretty cool. Just like in the sci-fi movies!
  11. Feb 3, 2006 #10


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    When I read the question, I thought the OP was talking about infra red spotlights mounted on CCTV cameras. You can't really see the beam, but you can definitely see the spotlight itself, some red light gets through the filter.

    Yes? No?
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