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  1. #11

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    Quote Originally Posted by DREW WILEY View Post
    All these accelerated fading testing methods have their flaws, and none is a real substitute for real time ...
    Hi, I've never seen any real flaws in the Arrhenius testing method, anything specific you could point out?

    For those who don't know what it is, this method uses a handful of test samples "aged" at different temperatures. As each sample reaches an endpoint, for example a 20% density loss, the results can be plotted on a graph, using scales = 1/absolute_temperature vs the log of time. If results fall on a straight line, this can be extended to any (lower) arbitrary temperature, and the predicted time to reach the endpoint can be read off the other axis.

  2. #12
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    And, it works for light fade as well provided that there is no oxygen diffusion problem or other such odd effects.

    PE

  3. #13

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    My take on the situation has never changed. If you want something to last for the ages, use optical-method conventional silver B&W, toned. For color, the test of time still has Kodachrome as the world's champ. I don't listen to much other claims. I fully realize an E-4 or C-22 is still out there, pretty as ever. But life's too short for me to look for one somewhere. Inkjet, schminkjet--that ain't photography.

  4. #14

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    Sorry Bill, I really can't get into this much without getting long-winded. I'm pretty familiar with this and that, not only because of years of color printing experience, but also due to an analogous background with industrial pigments. Tests help, but there are far far too many variables out there to make simple extrapolations dependable. And like I said, there is almost always a BS coefficient in there somewhere form the marketing side of things too. Wilhelm obviously did everyone a favor by getting the conversation in high gear, but I found a lot of his conclusions rather simplistic, and not really matched to my own actual experience with prolonged tests - at least going forward in contrast to observing how older media had actually held up. Lots of his idea fall apart badly when very complex formulations like inkjet get involved (which should never be called true pigment prints to begin with). And few things fade in a straight line. Aardenburg has formulated some testing methods which fill in a number of the gaps left behind by Wilhelm, and do address the complexities of inkjet in a more realistic manner. But nothing is perfect. Even the Sphinx of Egypt isn't truly archival. If it's original architects viewed it today, they'd probably go into shock.
    We have to be satisfied with "improvement". ... or else accept the fact that following generations will inherit more truly mediocre images
    than ever before. Fortunately, many of these will exist only on discs, which will come in practical for skeet shooting.

  5. #15
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    I am finding the information here interesting. I know full well that marketing spin is just that, so it is good to read concepts and real information relating to the subject.

    Marketing and advertising material can be true or misleading. The mere fact that it is composed by people trying to sell me something is enough to take it with a grain of salt and think for myself. Even if my thinking is flawed, at least _I'm_ doing it and not letting others think for me.

    One problem I have in real life is many people I talk to believe any marketing material they are exposed to, and sound like a TV commercial when we discuss things like photography, cars, food, etc.
    Truzi

  6. #16

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    Drew, you understand that I have to reject your position, that the Arrhenius testing method is flawed, if you can't give any hard examples. I know there are possible issues with inkjet, but as APUG is specifically not a digital site, I think we have to stick with chromogenic dyes. With that limitation, I'm not aware of any flaws with the Arrhenius test method.

    I worked for a large finishing chain for quite a few years, where I set up an image-stability testing program, so I have some experience with this. Although we did NOT do Arrhenius testing ourselves, we had such data from some of our suppliers. (Konica's SR-100 "Century" paper's projected lifespan was based on Arrhenius tests.) As part of our our own testing program, we also held long-term room-temperature test samples, and I don't recall ever seeing any of these fall outside a predicted tolerance range.

    I don't believe there is any such thing as a "BS coefficient" for Arrhenius testing.

    Quote Originally Posted by DREW WILEY View Post
    Aardenburg has formulated some testing methods which fill in a number of the gaps left behind by Wilhelm, and do address the complexities of inkjet in a more realistic manner.

    Drew, I wish you would be more specific instead of making vague innuendos. The only thing I can think of that you might be speaking of is the so-called "I* Metric." Mark McCormick-Goodhart (Aardenburg) says on his site that he invented it. But strangely, his 2004 paper describing it is also coauthored by both Wilhelm and Dmitriy Shklyarov. (It's called A "Retained Image Appearance" Metric for Full Tonal Scale, Colorimetric Evaluation of Photographic Image Stability.) Also, in McCormich-Goodhart's "About the Author" section, it says "From 1998-2005,he collaborated with Henry Wilhelm of Wilhelm Imaging Research, Inc to develop new image permanence test methods for evaluating modern digital output media."

    Apparently the two companies, Aardenburg and Wilhelm-Research, have different goals, but I've meandered on long enough, I think.

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