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B&w to color

  1. Jan 10, 2010 #1
    isn't that different intensity of black and white in an old B&W photo correspond to a particular color range of the source.
    Which can then be converted into its original color?
     
  2. jcsd
  3. Jan 10, 2010 #2

    russ_watters

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    No, different colors do no conform to different intensities - play with a color photo and a photo editor and this will become clear to you.
     
  4. Jan 10, 2010 #3
    My dad, who grew up watching black and white films, claims he can tell the difference between colors in a black and white movie.

    Whether or not I believe him is a different thing.

    Also I kind of like the contrast of black and white. I think it makes things crisper than a lot of color movies.
     
  5. Jan 10, 2010 #4

    russ_watters

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    You sure that isn't just for objects he already knows the color of?
     
  6. Jan 10, 2010 #5
    Edwin Land, inventor of the Polaroid camera, would sometimes demonstrate the recreation of an (apparent) color image from two black-and-white slide transparencies using two projectors. Each projector alone projected a B&W image, but both together projected a color image. Here is a website discussing his technique.
    http://people.msoe.edu/~taylor/eisl/land.htm [Broken]
    I saw Edwin Land demonstrate this in the 1960's, and was totally surprised by the result.
    Bob S
     
    Last edited by a moderator: May 4, 2017
  7. Jan 11, 2010 #6
    when a color photo is converted into B&W, could that B&W photo be similar to the same souce but with some color changes and converted back into B&W
    OR
    does any intensity of Black or White correspond to more than one color
     
    Last edited: Jan 11, 2010
  8. Jan 11, 2010 #7
    Part of it is the shade of gray, the other part is his knowledge that a banana is yellow, and not pink.

    As for colors of unrecognized objects, I don't think so...
     
  9. Jan 11, 2010 #8

    russ_watters

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    Interesting experiment, though your description is somewhat inaccurate. One of the black and white slides was shot with a red filter, then projected with a red filter. So it is truly a red image through and through. Digital cameras work the same way, by using alternating colored filters on a monocrhome CCD.

    He didn't prove you can see color in a black and white image, he proved you can see all 3 colors in a red and white image. I suspect, though, that a lot of the reason this works is that there are similar proportions of blue and green in that image. I'll check into it with Photoshop when I get home tonight...
     
    Last edited by a moderator: May 4, 2017
  10. Jan 11, 2010 #9

    russ_watters

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    As I said above, any color can have any intensity. It would help a lot if, as I said above, you play with a photo editor to demonstrate for yourself, but here is a brief description of how a color image is represented digitally:

    Each of the three colors is assigned a brightness level from 0-255 and the three are then combined in each pixel to generate a color image. So you can have a pixel with any combination of brightness levels for each color, giving 256*256*256=1.67 million different colors.
     
    Last edited: Jan 11, 2010
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