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  1. #11
    mikewhi's Avatar
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    Hi Mr. "127" (btw, whatever happened to 000-126? We all know about 007)

    I'm not that tecnhical that I could plot this, so I need help intrepreting the graphs. Are you saying that for the first scan with EFKE 25 that the only light passed thru the filter is the small area under the red curve that crosses over the 3rd and 4th section of the graph? All other light is either blocked by the filter or is not rendered by the film?

    -Mike

  2. #12
    127
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    Quote Originally Posted by mikewhi
    Hi Mr. "127" (btw, whatever happened to 000-126? We all know about 007)
    Well 126 died a horrible death sealed in a little plastic cartidge...


    Quote Originally Posted by mikewhi
    I'm not that tecnhical that I could plot this, so I need help intrepreting the graphs. Are you saying that for the first scan with EFKE 25 that the only light passed thru the filter is the small area under the red curve that crosses over the 3rd and 4th section of the graph? All other light is either blocked by the filter or is not rendered by the film?
    Basically yes.

    The white curves are the response of the film vs frequency. The vertical lines mark 400,500,600nm - the approximate divisions between uv,blue, green and red. Efke 25 doesn't respond to much above 600 (ie in the 4th section), as it's basically insensitive to red.

    A 25 filter is the top red line, so if "white" (thats a whole other ball game!) light where to hit the filter, only the stuff under the curve would reach the film.

    Combine those two lines and you get the lower red curve. That is the effective light which reaches the film and then actually has some effect on it. The area under the final curve is what matters, but for this combination it's not very big.

    I compared the area under the original film curve, with the final curves area to estimate an exposure compensation.

    However to do this properly you need to take into account the original light, which isn't exactly "white". Ideally you'd have a spectrum for the light, multiply that by the spectrum of the subject, multiply that by the filter, then by the film to give a final spectrum. Compare that with and without the filter, and you have a totally accurate exposure compensation.

    Ian

  3. #13

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    WEell, all I can add is that I took the same scene with a red filter on the EFKE 25 and then put in a holder with TMAX 100 and shot the same scene with the same red filter on. I will process them in a few weeks when I get back from my trip and see if anything usable comes out. If so, I'll scan the negatives and post them in the technical galelry for general interest, if any.

    Thanks for your help!

    -Mike

    P.S. I guess the EFKE will come out very thin as I only gave 3-stops extra exposure for the filter. Hope the TMAX negatives are good because the scene was lovely, high altitude, sotrm clouds interesting hills in the foreground, sage brush, etc.

  4. #14
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    Please post your results when the film is done so we can see. I don't use a red filter with Efke 25 and am curious about a side by side test showing the difference. Contrast may be a problem, but post it anyway if something shows up.

  5. #15

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    Just out of curiousity, AA has a picture in one of his books of a deep conifer forest scene, with nice tonal separation on the trees and open shadows, shot using a 44A filter, which he says gives an 'orthochromatic' response. Would Efke-25 unfiltered mimic that look? It would make it an interesting woods, foliage, and jungle film in that case.

    (I know, I know, order a couple of rolls and go find a pine tree to get a real answer)

  6. #16
    127
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    Any Mac users out there intrested in playing with some software for plotting graphs like the ones I posted a few days ago? I've been playing with the software, and it's in a state where its now in a relativly usable form. It's still a bit rough in places (and could do with more data being loaded into it!), but it's starting to be fun to play with.

    If you're interested, then PM me and I'll send you out a beta copy.

    Ian

  7. #17
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    I have processed the EFKE 25 negatives taken with a Red #25 filter. I gave 3 stops more exposure for the filter factor.

    The negatives look better than good. Lots of contrast and detail in the lower zones and the cloudy skies are great.

    I"m very pleased with the way the EFKE 25 negs came out with the red filter.

    I am developing the TMAX 100 negs next in Pyrocat-HD to compare with the EFKE film.

    Prints in a week or two.

    -Mike

  8. #18
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    Whew. I've processed a lot of 5x7 negatives so far. They're washing now. I really like the EFKE 100 negatives, too.

    I'm gonna pop open a bottle of wine and have a glass or two while they wash.

    Anyone want to join me?

    -Mike

  9. #19
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    I'm up to over 50 5x7's developed so far. All EFKE film and a few more to go. Then on to the TMAX 100 5x7 in Pyrocat HD. Then the 8x10 EFKE and TMAX 100 and some rolls of 120, too.

    Wine is still holding out, more bottles in the pantry if needed!

    -Mike

  10. #20
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    Mike, if you run out of film, do you buy more and then run out of wine? This is sort of like chocolate sauce and ice cream.

    "Opps, I ran out of ice cream and have too much chocolate sauce left in the bowl, so I added ice cream. Now, I've run out of sauce for the ice cream so I'll have to add more and, oops, I'm out of ice cream again so...."

    Still want to see the Efke 25 and 25 red filter prints when you get them done. I'm wondering if the filter is the hot tip for cutting down contrast for better control with this flashy beast of a film.

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