Magnet and film --- damage?

Discussion in 'Film and Processing' started by dakota_lost, Mar 27, 2004.

  1. To what extent, if any, can a magent damage a roll of film that is
    unused or unprocessed?
  2. It can damage it pretty badly if it's a big magnet and you smash the canister with it hard enough.
  3. It shouldn't do anything.

    Well maybe if you had the worlds most powerful magnet it might rearrange something at the atomic level, but film shouldn't be affected.

  4. I work in Physics lab where the large electromagnets do damage people's laptop computers, electronic watches and credit card memory strips, but never to film.

    X-rays on the other hand are a whole different kettle of fish.
  5. A magnet could damage information on APS film.

    Ron Mowrey
  6. I was out today and had my camera case in the back seat of my pickup. I didn't noticed it until a while later, but I had set the case in front of one of the 6x9 inch speakers that is mounted in a wooden box in the back seat. The film was in the case (a Promaster roller case) and was about six inches from the speaker magnet. Keep in mind that the magnet is inside the wooden speaker box. Could it have caused damage?
  7. Score one for Ron on the APS!

    Otherwise, no: The silver in the film is non-magnetic.
  8. Thanks. Sorry if I sounded foolish. Just wanted to make sure.
  9. Ask a stupid question and you're a fool for fifteen minutes. Don't ask it and you're a fool forever.
  10. I suppose it is possible that you could damage cameras in different ways with strong magnets. But not film.

    Also, the metal detectors at the airport shouldn't damage film at all (unlike the xray machines.)

    I once had a compass get reversed when my kid was playing with it and a speaker magnet. I figured the needle would just align with the field, but no, the needle got reoriented 180 degrees off.
  11. NO. Your question suggests you confuse elecromagnetic sensitive material like audio or video tape with light and chemically sensitive material like film. Film is not affected by electromagnetic fields but by Xrays.
  12. If your speaker was overdriven (be it from an underpowered amplifier that was clipping or a strong amplifier that was excursing the speaker's coils to their limits ) to the point that it became hot and the film was close enough to absorb some heat, then it might alter the film.
  13. A stationary magnetic field will attract a ferromagnetic metal such as iron, cobalt, or nickel. Not found in film.<BR>
    A moving magnetic field will generate currents in any metal, including silver. Faraday's Law.<BR>
    But undeveloped film contains only silver halide compounds such as silver iodide, bromide, etc. The only metal is in the form of very small groupings of silver atoms on the edges of grains which constitute the latent image. This conversion of silver halide to silver atoms must be caused by a photon, be it a visible or x-ray photon, etc.<BR>
    It couldn't add dots to the latent image because it could not remotely have an effect on the non-latent-image silver halide grains as they do not conduct.<BR>
    And magnetic fields have no effect on photons, just electrons.

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