If an image can be left on photographic film and be processed so that it can be

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   Tusitala Tomposted 13 years ago

   If an image can be left on photographic film and be processed so that it can be seen, is it...
   
   possible that images are also left on brick walls, fences, and other standing objects and that, with the right sort of equipment, they could also be seen or sensed?

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2. 75

   RocketCityWriterposted 13 years ago

   Of course, take your brick wall example. If a person is standing in front of a brick wall and the sun is shining such that a shadow is cast upon the wall, then that could be an image (or the negative thereof). Or if you took an infrared camera and looked at the wall, you would see an image of the person's profile due to the blockage of the warm sunshine against the wall.
   
   Another way of looking at the brick wall scenario (and probably more of what you were thinking) would be to measure the radiation from the human body that impinged upon the wall. Possibly some form of gamma ray or xray radiation might alter the wall such that you could detect the alteration in the wall and capture in an image. It wouldn't appear like in image in the traditional sense of photographic film, but it would be an image nonetheless.

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   MickSposted 13 years ago

   Probably not, the sun bleaches, if you stand against a brick wall long enough the wall will be bleached around the area that you blocked leaving a silhouette on the wall.  Of course the rub is in the, long enough, you would be dead, the sun cant bleach quickly enough.  if we think of a piece of photographic film that is exposed every time some one walks past it, then it won't take long for that light sensitive material to become an unreadable, overexposed mess, if a wall had the same type of sensitivity to light it would be overexposed long ago, the technology we have at the moment would not be able to retrieve and separate any images it carries.

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   s.wilsonposted 13 years ago

   With current technology, I don't think it is possible without causing great harm.  The atomic bomb dropped on Japan during WWII burned some shadows into sidewalks, but this was due mostly to bodies blocking out the excessive heat. 
   
   The way that a camera film works has to do with chemical reactions that react to light.  With digital cameras, it has to do with light reactions within a sensor being recorded onto a storage device.  Neither of these could be exposed for long periods of time without distortion, especially with fast moving subjects.
   
   This is not to say that it may not happen in the future, but with our current amount of technology, photographs are the way to go.

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