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  1. #1

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    Ektachrome history

    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.

    I'm kind of currious also, how did these images look like.
    Has anyone actually seen such an old corrected Ektachrome image that hasn't faded beyond uncorrectability?

    The curves in the article suggest it had a much lower density range
    than modern E6, or even Ektachrome 25.
    The blacks must have looked a little thin, and judging by the curve, the whites looked pretty dirty too.
    What is interesting is that the slope of the straight portion is milder than of modern films, and it has a GIANT toe and sholder, nothing like new films.
    So the straight portion is way shorter.

    I actually overlayed a modern film curve over this one (stretched the graph to precisely match desnity and exposure scales) and the difference is pretty big.

  2. #2
    Photo Engineer's Avatar
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    Sounds like the original Ektachrome film to me. It was out about then.

    That was a 75 degree process and the examples I have have faded badly. Several of my slides were used in the new book by Ctein on digital restoration of photographs.

    I processed these when I was a teen.

    The C-22 negatives from that time are still ok, but the Ektachrome has been gradually turning red. The Ektachrome was grainy and not very sharp. Blacks looked good (at the time). The color was quite nice, accurate but not overdone. The speed was not more than 25, but I cannot remember for sure. I think it was though, because it took less exposure than the Kodachrome that I used at the time which was 10.

    PE

  3. #3
    Helen B's Avatar
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    I've got plenty of photo mags from the 50's and I'll look through them when I get back. Could you show us the curves from the article?

    Thanks,
    Helen

  4. #4
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    Quote Originally Posted by Photo Engineer View Post
    the Kodachrome that I used at the time which was 10.

    PE
    Interestingly Kodachrome at the time in roll film had a speed of 10, while the Professional Kodachrome in sheets was 6.

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    Quote Originally Posted by Helen B View Post
    I've got plenty of photo mags from the 50's and I'll look through them when I get back. Could you show us the curves from the article?

    Thanks,
    Helen

    Personally I have no problem with that, but those are not curves from the product sheet that Kodak usually publishes for free, but are actual results from the study (experiment). The study was originally published in a magazine, and is now being soled.
    So basically it would be piracy. I don't know what is the policy of this forum about that. I don't want to offend anyone around here.

  6. #6
    Helen B's Avatar
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    I'd be happy to buy the article - could you give us the reference?

    Thanks,
    Helen

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  8. #8

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    To give you some clue what it's about before you decide to buy..

    It's a short article showing the process through which they tried to come up with equations that will make density of every layer a function of exposure of all 3 layers. In other words they wanted to present interimage effects as a function.
    There are a series of tests with combinations of uniform exposures and step-tablet exposures.
    The test show how uniforme exposure of one layer is actually twisted by step-tablet exposure of the other layer, showing a negative image, made just through interimage effects without any exposure.
    Same is repeated for all layers.
    As a byproduct of this test, they came up with a standard characteristics curve for that film too, because they needed it as a reference.

  9. #9
    dmr
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    Quote Originally Posted by Photo Engineer View Post
    The C-22 negatives from that time are still ok, but the Ektachrome has been gradually turning red. The Ektachrome was grainy and not very sharp.
    Ektachrome seems to be inconsistent as to how the slides keep after 30 years or so. I shot a lot of it (I guess this would be Ektachrome-X and the original HS Ektachrome) in the early 70s. A few of them actually survived quite well (below) but quite a few have faded in the magenta direction and some appear to have gotten weaker in general but faded, if in the direction of any color, toward cyan.

    These three are fairly recent scans of Ektachromes I did in the early 70s. The two of the bridge and the tracks were on hazy days, and it does show.

    http://www.rangefinderforum.com/phot...hp?photo=15748
    http://www.rangefinderforum.com/phot...hp?photo=15793
    http://www.nycsubway.org/perl/show?41160

  10. #10
    Helen B's Avatar
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    Thanks Ed, I wouldn't want you to incur the wrath of the Optical Society of America just because of my curiosity. I'm a member, so I can get that article at a reduced cost.

    I kept many of my early Ektachromes frozen. Here are four examples of High Speed Ektachrome Type B from '73.








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