Wavelength response of first type of film with sound?

Discussion in 'Darkroom Developing and Printing' started by GreenXenon, May 12, 2009.

  1. GreenXenon

    GreenXenon Guest

    Hi:

    What wavelengths of light specifically affect the type of film used in
    the first movie containing an variable-density optical audio track? I
    am specifically interested in the chemical composition of the optical
    audio track.

    From what I know, most of the more modern films are unaffected by red
    light.

    I'm thinking of a theoretical device using analog audio recording on
    VD optical tracks containing the oldest film chemical composition. The
    source of light are multiple laser beams consisting of wavelengths
    that could record the audio onto the film. Each beam has a different
    wavelength. The beams are then mixed together to get a single beam of
    all the necessary wavelengths. The beam then shines onto the film to
    record the audio.

    I don't have much of an application here. I'm just in it for the
    science.


    Thanks
     
    GreenXenon, May 12, 2009
    #1
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  2. GreenXenon

    Pat Guest

    I have not idea, but Kodak has a museum in Rochester (NY). Call them,
    they might be able to help.
     
    Pat, May 12, 2009
    #2
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  3. GreenXenon

    GreenXenon Guest


    Blue takes up less space than green [for the same amount of data], so
    I'm guessing blue would make more efficient use of the film's length.
    This is because blue light is of shorter wavelength than green light.
    Per area, blue can represent more info than green.

    What is the best wavelength of blue to use?
     
    GreenXenon, May 12, 2009
    #3
  4. Aren't the things you're comparing here (the wavelength of light and the
    density of audio "data" on film at ordinary projection speed) many
    orders of magnitude different? Sounds like a silly distinction between
    colors.
     
    David Nebenzahl, May 12, 2009
    #4
  5. GreenXenon

    GreenXenon Guest


    What determines the highest-frequency sound that can be recorded onto
    a VD optical track?
     
    GreenXenon, May 13, 2009
    #5
  6. GreenXenon

    Peter Guest

     
    Peter, May 13, 2009
    #6
  7. GreenXenon

    Peter Guest

    The speed at which the film moves, the bandwidth of the transducer and
    the intensity of the illumination, are important factors. Near the
    limit of these factors, the performance of the film might be a factor.
     
    Peter, May 13, 2009
    #7
  8. GreenXenon

    GreenXenon Guest

    You say intensity of illumination. Does that mean that a more intense
    light can allow for a higher-frequency than a less intense light?

    By transducer, I assume your talking about the photoelectric cells
    that convert the optical signal playback from the film into an
    electric signal to be amplified and sent to a loudspeaker. Am I on the
    right track?

    As for the tape speed, does the nyquist theorem apply? If so, what is
    the minimum tape speed required to record a sound of 1 Hz? IOW, how
    high of a frequency is allowed per speed? In devices where sampling-
    rates are used, the sample-rate must be at least 2x that maximum
    frequency of the input signal.
     
    GreenXenon, May 13, 2009
    #8
  9. GreenXenon

    J. Theakston Guest

    Proof positive that a little information can do a lot of harm.

    J. Theakston
     
    J. Theakston, May 13, 2009
    #9
  10. GreenXenon

    GreenXenon Guest

    Thanks for your assistance. Sorry, if my posts were offensive to you.
     
    GreenXenon, May 14, 2009
    #10
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