Kodachrome, view with 3200K or 5000K

Discussion in 'Color: Film, Paper, and Chemistry' started by retro film, Jan 20, 2013.

  1. retro film

    retro film Member

    Messages:
    19
    Joined:
    Jan 17, 2013
    Shooter:
    Holga
    So on the kodachrome data sheet, It says to use a 5000K illuminant for viewing, but then on the Spectral Dye Density chart it talks about viewing with a 3200K light. So which is it? view with 5000K or 3200K?. There should be a difference since 3200 K light is more orangish yellow, but the 5000 K approximates a neutral looking light, so these differences will have an effect on the appearance of the slide when viewed.
     
    Last edited by a moderator: Jan 20, 2013
  2. jp498

    jp498 Member

    Messages:
    1,465
    Joined:
    Oct 5, 2009
    Location:
    Owls Head ME
    Shooter:
    Multi Format
    The major difference will be the viewing light's relation to ambient light. Using a 3200k light in a normal daytime work environment would be too warm. Using a 3200k projector at night at home would seem quite normal color.
     
  3. AgX

    AgX Member

    Messages:
    12,221
    Joined:
    Apr 5, 2007
    Location:
    Germany
    Shooter:
    Multi Format
    It depends:
    if you mount a transparency box illuminating with 3200K light a transparency photograph made for 3200K, in a room generally illuminatined by 5600K ligh, then, depending on the luminance level between the room and the transparency, the photo may look quite warm if it makes only part of the field of view. Looking soly at the transpareny box, thus from nearby, everything would be normal again.

    The same for comparing a transparency made for 3200K illumination and a reflective print made for 5600K side by side:
    If the transparency box is masked to only show that transparency and the reflective light box has a black desk the print is lying on, everything is perfect.
     
  4. AgX

    AgX Member

    Messages:
    12,221
    Joined:
    Apr 5, 2007
    Location:
    Germany
    Shooter:
    Multi Format
    You are mixing things up:
    -) the intended viewing situation of an unfiltered transparency (exposed by illuminating a scene with standard light)

    -) a laboratory made graph intended for comparison (where by added filtration the layers are exposed to yield a neutral grey).

    Don't put too much emphasis to these data sheets. For instance, those spectral-dye-density curves are only recently added to those charts. And the interpretation of many graphs is beyond the command of the mean (including progessional) photographer. Furthermore the comparison between graphs of different manufacturers can become tricky.
     
  5. retro film

    retro film Member

    Messages:
    19
    Joined:
    Jan 17, 2013
    Shooter:
    Holga
    What do you mean by filtration? Do you mean putting a filter over the light source to make it a more neutral color?..I have read that the ideal visual neutral curve is said to be a flat horizontal line, but such a curve would only appear a neutral grey if the spectral power distribution of the light source were uniform. Anything that deviates from uniform would introduce a warm or cool tint to the grey(accept for maybe a 5000K, that approximately looks neutral).
     
  6. AgX

    AgX Member

    Messages:
    12,221
    Joined:
    Apr 5, 2007
    Location:
    Germany
    Shooter:
    Multi Format
    In doing that test that yields such a graph the film resp. the layers are exposed through filters, in a way that finally a neutral grey sample is repruduced to the eye as neutral.

    As said above I question the information value of these data sheets. Furthermore, looking at the sum of colour materials produced, for the majority of them I have never seen any data sheets, I even assume those graphs never left the plants.
     
  7. lxdude

    lxdude Member

    Messages:
    6,942
    Joined:
    Apr 8, 2009
    Location:
    Redlands, So
    Shooter:
    Multi Format
    I view mine on a 5000K light box. They look great.
    The bulbs were 6000K, but the slides looked cold (bluish).
     
  8. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

    Messages:
    4,578
    Joined:
    Oct 29, 2006
    Location:
    İstanbul
    Shooter:
    35mm RF
    I worked 4 years at an PrePress lab and my boss was a everything must be calibrated maniac. He was using a 3200 K top and desk lamp for looking transperencies , proofs and prints. We were the one of the biggest and most advanced lab in the world.