Except for six rolls of film that I shot in 1995 that got sealed in the Bicentennial Time Capsule which is now buried under the cornerstone of City Hall and won't be opened until 2095.
Originally Posted by eclarke
(It was Tri-X Pan. Unless there is a major disaster like a flood or a tornado, I have no doubt the film will last 100 years.)
PE is correct about fading. But there are negatives developed in Pyro (in all sorts of formulations) that have been going strong for over a hundred years and are still quite printable. There are also a lot more that have deteriorated for unknown (possibly multiple) reasons. So, treated properly, it is possible to get long life out of some Pyro negatives. We don't know anything about the archival keeping properties of modern films processed in modern Pyro developers, however. Since they all contain a fairly vigorous silver image, they should be at least printable, possibly with some deterioration, in the distant future if they were properly fixed and washed. It might be interesting to run an accelerated aging test.
The point that's constantly missed is the Pyro stains are very much more stable than any dyes used in colour films or prints, Kodachromes fade and disappear in 50 years but that hasn't happened to Pyro negatives as yet
Originally Posted by nworth
There's a vast wealth of knowledge about various archives of photographers who used Pyro negs and no mention of issues of the stain fading.
A very large number of people have made side-by-side comparisons of Kodachrome and other chromogenic films and they have determined the amount of fade under various conditions. These are before and after comparisons with data. So, we know that they fade. There is no data regarding pyro or stained negatives. So, we can't prove either way whether they are more or less stable than any other dye.
The yellow-green stain is similar to the old Quink Green Ink sold in the US, and it was made from HQ which was oxidized into the Quinhydrone form to make the greenish yellow colored ink tint. This tint fades as I well know. All notes I took in green ink are virtually gone today. All dyes fade. This is a property inherent in the process which imparts their color. They absorb energy from light, heat and etc and gradually fade.
As I said earlier, no one can prove one way or another, but based on scientific fact, they fade. Just because there is no proof does not mean that they are stable.
Don't be so sure. As rolls, they were on acetate base. When that capsule is opened, they could be a vinegary blob. Shoulda shot polyester-base sheets.
Originally Posted by Worker 11811
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The stain in Pyro-developed films seems to me to be much more that a "dye". It's actually a chemically bonded cross-linking of gelatin molecules, which happens to have light absorbing properties.
I'm certain the cross-linking can be broken, but it appears the rate with normal storage conditions is not very great. Keep in mind that strong light storage is probably not going to be good for them.
I've no testing to support my suspicions, but based on anecdotal reports of the condition of properly stored vintage negatives, I suspect that "pyro-stained" gelatin should last about as long as the gelatin itself.
I guess we need the Wilhelm group to do a small test for us...
For up from the ashes, up from the ashes, grow the roses of success!
It would be interesting to see that data.
Originally Posted by Ian Grant
That would be an argument in favor of a staining developer.
Originally Posted by Ian Grant
Point taken. On the plus side, we knew what we wanted to do from the beginning of the project. The film was processed by a local lab with specific instructions that they were going in the time capsule. They were supposed to be placed in polyester sleeves and sandwiched between layers of acid free paper (or something like that) in hopes that the paper would absorb and/or buffer any acetic acid vapor given off.
Originally Posted by Sal Santamaura
The capsule, about the size of a casket, is buried six feet under ground. It was supposed to have been vacuum sealed before it was buried.
Temperature should not be a problem because the temperature under ground never goes much above 50ºF.
If I remember correctly, a set of 4x6 B/W prints was also supposed to have been made and interred with the film.
It's been 17 years since it was buried. Memory fades...
My wife is an administrator at the local Historical Society. That's how I got the gig. (It was actually before we got married.)
I suppose I could ask her to look up the details.
Thanks for the information and comments. With all the work that has been done on the archival aspects of silver negatives and prints it is surprising that very little has been done on the useful image life of negatives developed in pyro...or at least it is much harder to find. If you google something like "photographic conservation pyro negatives" you get some references, but I've found nothing yet specific to the subject.
As Photo Engineer noted dyes do fade, but Kirk considers the stain "to be much more than a 'dye.'" Obviously if it were a "stain" akin to rust (iron oxide) it wouldn't fade in (literally) a million years. As nworth noted even if the stain faded there is still silver there to make an image, but I wouldn't imagine it would be a very ideal one.
Fading aside, there is also the issue of possible deleterious reaction between the stain and the other components of the negative such as gelatin, silver grains, substrate, etc. Kirk's note that the stain is bound with the gelatin strikes me as either comforting or scary...depending.
Anecdotal evidence (Ian and nworth) indicates that pyro-stained negatives 50-100 years old are still very useful. That suggests that for most of our work we really shouldn't worry very much. Still, as Kirk says, it would be nice to have some experimental evidence...