EIR colours

Discussion in 'Color: Film, Paper, and Chemistry' started by Stan160, Aug 13, 2007.

  1. Stan160

    Stan160 Member

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    I have just tried Infrared Ektachrome for the first time, and love the results! Too bad it is discontinued, have ordered 10 rolls for the freezer which is all I can afford at the moment.

    One question: Although very pleased with the results, I don't understand the way the colours have come out. The document at http://www.kodak.com/global/en/professional/support/techPubs/ti2323/ti2323.jhtml indicates that with a yellow filter (which I used, a Hoya Y48) colours are shifted infra-red to red, red to green, green to blue, and blue to black.

    This is a scan of one of my pictures http://farm2.static.flickr.com/1426/1075043854_665352d099.jpg. It was a bright sunny day, so I understand that the foliage is reflecting a lot of IR, which shows up as red, but I don't understand how the areas not reflecting much IR are similar to the original colours - shouldn't they be shifted? In particular, the sky should be black according to the documentation.

    Thanks,
    Ian
     
    Last edited by a moderator: Aug 13, 2007
  2. ben-s

    ben-s Member

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    I have found the colours to be different to what Kodak say.
    Skies tend to be light blue, even with a yellow filter. EDIT: Rather like your example /edit
    Some of my favourite EIR images have been taken with no filter at all.
    It's a pity it's up for discontinuation - Although expensive, I enjoyed using it. (well, with the exception of the estar base - a pig to load into patterson reels for processing...)
     
  3. Robert Hall

    Robert Hall Subscriber

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    EIR has quite a blue cast. I use yellow and orange filters to change the colors a bit, cutting down on blue.

    The best way to know what colors to expect is to shoot a lot of IR film.

    I would worry more about exposure than what colors they turn out, on which, you have done a good job.

    I also find that the exposure latitude is very tight. Over exposure is pretty much a waste with slide film, but a 1/3 under exposure is worth looking at.

    Here are some of my examples http://www.roberthall.com/missions.html
     
  4. Stan160

    Stan160 Member

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    As this was my first roll, I set the meter to 200 as recommended and bracketed one stop either side.

    The -1 stop exposures were the ones that turned out best, the example I posted is one of these. The meter in this camera is accurate enough to give good results with Kodachrome and Elite Chrome at their box speeds so I guess I will be setting it to 400 for the next roll of EIR and will try the -1/3 stop you suggest for comparison.
     
  5. Robert Hall

    Robert Hall Subscriber

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    One stop was way too much for me. The slides would be much to dense or really thin. I set the above examples on an N90s (Nikon) to 320 and shot spot on and somtimes improved with a 1/3 underexposure. (this was, of course, "through the filter" metering.)
     
  6. Silverhead

    Silverhead Member

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    You hit the nail on the head with your last observation, Stan--not every color shifts with EIR all the time - it depends on what the material the object in question is made of. The more organic components in the object usually means more IR response, and thus a better color shift. For example, metal surfaces very often shift very little, or not at all...silver & chrome especially. In your case, the stone castle and the road are not shifting very much because neither stone nor asphalt(?) contain enough material to generate the IR response. Example of mine: a number of years ago I did some oceanside shooting in Santa Monica, and shot a wave crashing on a barnacle-encrusted rock. The rock did not shift at all (though the color was a bit deeper than the original), but the barnacles turned bright red. Reason: barnacles are organic, rocks are not.

    As far as the sky goes, that is dependent on a number of factors - time of day, the angle of the shot & the sun, how much blue is in the sky that original day (i.e. how hazy is it?), and others. In general, skies that have a good amount of blue in them on that particular day become deeper blue. If you use a polarizer, you can go all the way to black sometimes. Without one, late afternoon shots can generate really deep blues when the camera is pointed toward the east when the sun is getting ready to set in the west.
     
  7. Photo Engineer

    Photo Engineer Subscriber

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    We had a thread on this before, and I'm not sure I responded correctly even though I used a lot of it in the AF.

    Basically, the blue + IR sensitive layer forms a cyan image. So, when processed, where there is lots of IR light, a cyan image forms. So, Red, Greens and Blues contain cyan. There is no cyan in pure IR with this film.

    The Green sensitive layer forms a yellow image and therefore Blues, Reds and IR contain Yellow.

    The red sensitive layer forms a Magenta image and therefore Greens, Blues and IR are Magenta.

    The combinations are thus, IR is red, Red is green, Green is blue and Blue is black.

    The subtractive colors C/M and Y would be complex mixtures with lots of variation depending on IR just as the above.

    This shift is not possible when using digital cameras as they only record IR + their own color. Therefore a totally different image results.

    PE
     
  8. ben-s

    ben-s Member

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    PE; An informative post - thanks!

    Here's one of my EIRs
    It exhibits the same blue/purple cast as Ian's
    [​IMG]