paulr

Please excuse the very long post. I thought it would be worth it because so many photographers here are concerned with image permanence, and because the information that's been shared with me here goes against a lot of the conventional wisdom.

Initial questions were raised in this thread: http://www.largeformatphotography.info/lfforum/topic/502249.html

I had brought up some issues based on an old research paper that I'd found, and on dodgy memories of some other things I'd read a long time ago. But I couldn't answer a lot of the questions being raised. Happily, someone put me in touch with Douglas W. Nishimura, who's a Senior Research Scientist with the Image Permanence Institute at Rochester Institute of Technology. He may know more about this issue than anybody.

The reader's digest version is this: selenium toning is not very effective at protecting silver prints from deterioration, unless toning is carried out to an extreme degree. Gold toning is better, working at much lower doses. Sulfide toning is better still. Most surprising of all, incomplete washing of the prints, leading to trace amounts of thiosulfate in the paper, may actually improve permanence. But there are many caveats and twists and turns. It's worth reading the full text if it doesn't make your eyes glaze over.

Read the full text of Doug's note on Toning and Permanence

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Kirk Keyes

So does that mean we should be using a iodide final rinse to try and prevent the oxidation of the image? He kind of dropped that line of thinking and moved on to the sulfide/selenium stuff...

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Kirk - www.keyesphoto.com

Jan Nieuwenhuysen

Thank you for a very interesting post! Maybe this can be put somewhere on the permanent pages of this site?
This issue was raised during a 'preservation issues' masterclass I participated in last year at our national collections institute, but the discussion was rather inconclusive. Everybody knew what Wilhelm had said on it in his book (e.g.: Ch 17, note 23) , but not the actual chemistry behind it. It sort of kept nagging me at the back of my head.

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Jan

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Henry Ambrose

I second Jan's idea to add this to the static content. The thesis (or a summary of it) referred to in the last paragraph would be a great addition as well.

Thanks paulr

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Andre_941

I can't read that. Anybody - what was the gist of it?

Andre_941

O.K., that's better. Thanks Ken.

paulr

"Bottom line is that it looks like Kodaks current claims about all of their toners helping preserve is probably correct, but in the case of the selenium formula, it probably isn't the selenium that is responsible."

Ken, how are you drawing this conclusion? Their conclusions were that selenium toning needed to be carried out to an extreme degree to make a significant difference.

In their testing the exception was an old batch of rapid selenium from the 80s that was more effective. They theorized about why that particular batch was better (contaminants, etc.) but were unable to come to any solid conclusions.

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Paul Butzi

Is it just me, or does the fact that the archival properties of an entire generation's worth of photographs was dependent on misunderstood (and unobserved) presence of contaminants in Kodak RST make anyone else view the various claims for longevity of gelatin silver prints with a high degree of skepticism?

Or am I the only one who's observed that an entire decade's worth of my prints, all carefully processed according to the much touted 'tone in Kodak RST' for archival results, are probably not protected?

It all raises the question - can anyone point to published longevity tests for any currently manufactured gelatin silver paper?

It seems that, regardless of process used, longevity is a crap shoot. You pay your money, follow the 'current best practice', and take your chances that none of the manufacturers will change suppliers and render all your careful processing worthless.

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paulr

Crap shoot is about it. That's how it's been throughout history. You could say that only now do we have reliable information on the stability of processes used during the renaissance. All we had to do was wait 400 years to see what happens (of course, the challenge now is to figure out what the work looked like THEN).

The difference is we now have at least some guiding science, even if most of the data is speculative. Better to have some educated guesses than none at all.

And there's one thing that's always been true: storage conditions are really important. Unfortunately, this is the hardest factor to control if your work doesn't end up with a rich institution.

For some perspective, remember that archival standards are really high. They're not based on when your work will completely self-destruct--they're based on when there will be a significant change in color or density. By these standards most of the old paintings on museum walls would fail outright. Some pigments have faded, others have changed color, varnishes have yellowed, dirt and soot have infused outer layers--but the work is still beautiful, it still effects people, and only the conservators seem to know that it's changed at all..

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"Life isn't worth living unless there's a camera around."
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David Luttmann

That's about it Paul. It appears that inkjet printers get derided for longevity issues because their prints may or may not last 5o, 80, 100 years. However, we also hear of color and B&W film & prints fading, or experiencing color or tonal shifts in less than 30 years. It is evident that there is an inherent weakness in every piece of the photographic chain, whether your capture method is film or digital, and your output is silver, pt/pd, inkjet, etc.

This is a fascinating time to be working with photographic materials. Longevity is discussed more now than ever....probably more than it need be. But discussions like this will benefit both users of analog and digital capture and output.....and the purchasers of our work.

Regards,