Collodion sensitivity to Tungsten

Discussion in 'Alternative Processes' started by Goza, Mar 15, 2009.

  1. Goza

    Goza Member

    Jul 13, 2008
    Los Angeles,
    8x10 Format
    I work in the Film Industry as a grip, and electric; work is very slow right now and I have alot of tungten lamps (mole richardson) sitting around that aren't being rented. So I decided to do a casual test with the wet-plate collodion process to see if I could get an image. All scenes were shot with the same exposure and waterhouse stop.

    First I shot a model outside in sunlight... 4000 foot candles, Kelvin 6000, exposed for about a second.

    Second, shot model on a soundstage with an array of 10K Tungsten lights...4000 foot candles, Kelvin 3100.

    Third, shot model on soundstage with an array of 10K Tungsten lights gelled with Color Temp. Blue Gel... 4000 foot candles, Kelvin 6000.

    From reading and word-of -mouth I had gathered that collodion wet-plates were only sensitive to daylight and sensitivity fell off dramatically towards Kelvin 4000.

    So I though going in that I would get a much more underexposed plate from the tungsten lit scene than the daylight and color corrected scene.

    But the result proved me wrong...all 3 plates were identical in exposure.

    So then I shot all the scenes with 2000 foot candles and the same color temperatures used in the first round.

    The result...still all identical.

    There were a few more rounds of test but at this point I want to ask for some feedback.

    The bulbed use was DTY, 10,000 watts, color temp of 3200 Kelvin (Listed), and its' distribution of energy favors the red end (647-700nm) of the visible spectrum (400-700nm), yet actually peaks in the infrared region and is extremely low in the ultraviolet section.

    Any thoughts?
  2. nawagi

    nawagi Member

    Mar 29, 2006
    Large Format
    HMI Pars


    Interesting test. When I shoot wet plate indoors I try to get a HMI Par or two- they have a great blue spectrum output that the collodion is sensitive to. Plus, the output is strong enough to bounce off showcards and get a very nice soft light. Haven't tried it with a Chimera Box yet, but that's next.