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Thread: Technical & Identification Questions about this Photo

  1. #1

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    Technical & Identification Questions about this Photo

    Identification
    I photographed this screen on the USS Yorktown aircraft carrier, which was first commissioned in 1943 and then repurposed a couple of times before finally being decommissioned for the last time in 1970 as explained here. Is the subject a radar screen, a sonar screen or something else?

    Technical question about color
    I photographed the screen because of the red reflections that had the ambiance of mid-20th century technology displays and because the room was lit by red lights very much as were used in photo dark rooms. I was shocked upon capturing the photo to realize that the frame on both sides of the screen, which was not remotely red to the human eye, is intensely red in the image. I'm guessing that this has something to do with the sensor capturing a portion of the spectrum not seen by the human eye but it's only a guess. Am I close?


    Technical & Identification Questions about this Photo

  2. #2

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    Re: Technical & Identification Questions about this Photo

    Quote Originally Posted by Mike Buckley View Post

    Technical question about color
    I photographed the screen because of the red reflections that had the ambiance of mid-20th century technology displays and because the room was lit by red lights very much as were used in photo dark rooms. I was shocked upon capturing the photo to realize that the frame on both sides of the screen, which was not remotely red to the human eye, is intensely red in the image. I'm guessing that this has something to do with the sensor capturing a portion of the spectrum not seen by the human eye but it's only a guess. Am I close?
    Technically, not close at all, sorry.

    Cameras have filters inside to specifically block invisible light. However, with actual real red lighting your camera white balance settings do not include one for that lighting, so stuff lit by a red lamp remains red.

    A grossly simplified explanation, pardon my lack of pedantry

  3. #3

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    Re: Technical & Identification Questions about this Photo

    Thanks for the explanation, Ted, especially for the simplistic characteristic and lack of pedantry. It makes perfect sense even to this non-technologist.

  4. #4

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    Re: Technical & Identification Questions about this Photo

    This looks a lot like a maneuvering board.

  5. #5
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    Re: Technical & Identification Questions about this Photo

    Red illumination, out side of a darkroom, is used to preserve dark adaptation. It can take as long as 30 to 45 minutes for human vision to become fully dark adapted, but the increased sensitivity to the low light conditions can be lost very quickly when any additional light becomes available, except for Red.

    If you ever attended an astronomical star party, this is the reason everyone is using Red illumination or have equipment with Red displays, or universally become outraged if a newbie turns on a white flash light / torch.

  6. #6

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    Re: Technical & Identification Questions about this Photo

    Thanks, Steaphany!

    Quote Originally Posted by JBW View Post
    This looks a lot like a maneuvering board.
    So, it is also a radar screen providing radar information that becomes part of the maneuvering information. The drawing in your link shows the maneuvering board as a horizontal table, whereas the subject in the photo is a vertical device, perhaps making it easier for everyone in the room to see it from any point in the room.

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