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  1. #21
    Photo Engineer's Avatar
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    The scan is fair. The blocking is partly an artifact of being exposed so as to insure a complete sensitometric scale is reproduced and some extra.

    However, this is pos-pos and that is typically subject to blocking anyhow as I have repeatedly said.

    PE

  2. #22
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    I might also point out that this was an experiment run nearly 25 years ago and just sitting around in an envelope in my darkroom. IDK what it even consisted of except that it demonstrates the general methodology of testing for you.

    So, please don't judge it or anything else I post as representative as it may not even have been any sort of a product. I merely had a sample sheet in my DR.

    PE

  3. #23

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    Ok, thanks


    @Helen:

    Did you read my post a few posts back (the question about your slides)?
    If you missed, it could you please go back?

    thanks

  4. #24
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    Hi Ed,

    I've seen it now. I can send you a much larger version, just PM me with an email address and maximum file size or a postal addres for a CD of the original file. I have more Ektachromes from the late 60s and early 70s, including the daylight ASA 64 version, and some were kept frozen as those four were. I'll dig the files out. Some were scanned at 8000 ppi at 16 bits on an Imacon.



    Best,
    Helen

  5. #25

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    Helen, I've sent you a PM.

    And thanks, really looking forward to seeing more of these old slides if you find any

  6. #26

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    Ron, do you happen to have any kind of characteristic curves charts for
    old (pre mid-70's) materials, either color negatives, color papers or
    reversal films?

  7. #27
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    Ed;

    The curves and sensitivities to light were pretty constant as were the speed relationships. What varied slightly were the dye hues and the toe and shoulder values. Speed increased, sharpness and grain changed. Dye stability improved 100 - 1000 fold.

    For example, Ektacolor professional paper was slightly softer in magenta toe, due to the fact that a hard toe caused cyan highlights in wedding gowns in professional wedding pictures, so there was a very tiny bias in the pro paper from neutral.

    Ektacolor 70 papers had a slightly redder magenta than type "C" papers in general, but the new Endura is slightly less red. It also had a new green sensitizing dye which is carried over into Endura AFAIK.

    Metamerism changed across the papers. Films were rather constant with broader dyes in negative films than in positive films, but with much more correction.

    I'm constructing this from memory as I have very little actual data. A few odds and ends.

    Dye stability variations seem to have been more process related than actual product related. This is based on personal experience and reading posts on PN and APUG.

    Bottom line is that negative films ran at about 0.6 - 0.65 contrast and the papers were kept at about 2.50 in contrast. There were minor tweaks in paper toe and shoulder.

    I hope this helps. I think I have an old aim overlay for color paper that I might be able to locate, but looking at the data on the Kodak web site, things look pretty unchanged to me. My contribution would be redundant.

    PE

  8. #28

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    Thanks, regardless , if you find anything please post, it would be interesting to see

  9. #29
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    Quote Originally Posted by Ed_Nyari View Post
    Hi there

    I bought a nice scientific article by Kodak engineers from 1952.
    They studied interimage effects in old Ektachrome type B film.

    Now I'm trying to figure out which film was that.
    Tungsten from 1952. I'd assume the ASA rating was about 12-16 , but who knows.

    So does anyone have any idea of what kind of Ektachrome films there were back then.

    I'd settle for a rough estimate of speed, so just shoot the lowest ISO you ever heard for Ektachrome, and what year was it.

    The film is sheet film, so it's either original E process or E3.
    Since it's 1952. I'd bet it's original Ektachrome process.

    ...
    US Camera of Feb 1951 mentions the 'new' Ektacolor Type B as having the same speed as Ektachrome Type B: Weston 6. That would be 8 ASA, wouldn't it? (But did the method change?)

    A Kodak advert mentions Ektachrome daylight in 120, 620 and sheets, and Type B in sheets only.

    1957 copies of US Camera mention 'New Ektachrome' as being 32 ASA, and available in 828, 127, 120, 620 and 135.

    Best,
    Helen

  10. #30
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    This has been a fascinating thread to read.

    Thank you, Ed, Helen and PE.

    My experience with Ektachrome was in the late 1970's through early 1990's as a (less than satisfying) substitute for Kodachrome when I wanted/needed a faster film. Then, KodaC only came in 25 and 64 (I'm speaking of 35mm here) and on cloudy days or at night - or when trying to shoot interior available light - EktaC was the only alternative at 200 and 400.

    Helen, your photos confirmed what I always felt was "wrong" (to me) about EktaC (too much blue/green) but I was somewhat surprised to see that it rendered some red/yellows better than I remembered. Of course, never as "vivid" as KodaC - but then KodaC was always a bit "over the top" with the red/yellow side.

    I want to go through my original slide collection that I scanned a couple of years ago when I get back down to NYC. Unfortunately, I mixed the KodaC and EktaC based on subject/time rather than film type - but I should be able to figure out which was which. I'd like to see again how my old EktaC rendered red/yellow.

    Perhaps they were "on" to something that Fuji finally accomplished with Velvia? It seems to favor the blue/greens - but still produces very nice red/yellows....

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