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  1. #11

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    Quote Originally Posted by dancqu
    That ISO is for speed. For color fidelity in a gray scale
    rendition, tungsten is used. Ilford, IIRC, uses 2850K.
    Interesting about the color fidelity - but I assumed he was testing for speed with my post.

  2. #12
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    Quote Originally Posted by dancqu
    That ISO is for speed. For color fidelity in a gray scale
    rendition, tungsten is used. Ilford, IIRC, uses 2850K.

    That temperature is used because of the limitations set by
    the green and red sensitisers. In other words a panchromatic
    film is no faster than its green and red sensitivities.

    So, for outdoor shooting don't forget your yellow filter. Dan

    I'm sorry, but you've lost me on this. Could you elaborate? Are you talking about paper? If so 2850K is close to the ANSI standard. ISO 6 says that film speed can be determined using ISO sensitometric daylight, studio ungsten, or photoflood illuminants as long as the conditions are stated in the instuctions. BTW, under 5.3.4 Filters it states, "ISO speed does not apply to the filtered conditions."

  3. #13

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    Quote Originally Posted by Kirk Keyes
    Interesting about the color fidelity - but
    I assumed he was testing for speed with my post.
    I think my response was more directed at the OP. He
    mentioned panchromatic and color.

    Due to the high level of blue light outdoors and films' high
    sensitivity to blue, there will be an over density in the
    negative. The film may be called panchromatic but
    it is over sensitive at the blue end.

    The Delta 3200 response curve specifies 2850K. There
    are some other curves, ie Pan F, with near exact same
    shape but do not specify. I think most pan films have
    near same "speed" from the deep blue well into the
    red at some tungsten kelvin. Note that the blue
    density is in line with the green and red even
    though we know tungsten to be very weak
    at that end of the spectrum.

    If I'd taken my own present advice years ago, I'd have
    an easier time printing clouds; the yellow filter. As for
    the OP, I'd suggest a 3400K source. Dan

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