Recently I found some old family photo albums that had been forgotten for years out in my garage. Though not exposed to water, the ambient humidity must have gotten somewhat high and many of the pressed together, facing pictures were stuck together. As I tried to pull them apart I noticed that the very oldest (1920's and '30's) of them came apart with gentle pressure and no damage to the the emulsion. I thought "Gee, they must have used some kick-ass hardener back then". Then I remembered that in my darkroom days, I would always mix my Kodak Rapidfix without the hardener because I was told that it permitted a more archival wash. Apparently those old guys had never been taught about archival printing because their emulsions are hard as rocks and after 75 years their casual snapshots still look like they were printed yesterday. What a bunch of dopes <g>.
Other observations, some of the later (1960's) B&W and color prints are going to have to be soaked to be separated. (I hope I can get some Photoflo somewhere). And, hands down, the absolute worst permanence offenders are commercial school photos. My advice is take any of them that you have and shoot copy negs if you plan to look at them when you are old and grey... or even youthfully middle-aged.
I could be totally wrong, but I believe that hardner wasn't added into fixer until the mid 60's.
I'm sure there is more to it than wether or not hardner was used in the origional processing. I'm sure the papers of the 20's and 30's where substancially different as far as the emulsion and paper bases are concerned.
In lew of Photo flo use a drop of liquid detergent, but neither is necessary when resoaking prints, only with negative developement is Photo-flo necessary to avoid water spotting.
</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (bmacphoto.com @ Nov 21 2002, 09:32 PM)</td></tr><tr><td id='QUOTE'>I could be totally wrong, but I believe that hardner wasn't added into fixer until the mid 60's.</td></tr></table><span id='postcolor'>
My 1943 copy of Kodak's "How to Make Good Pictures" lists only two fixers (F-5 and F-1), both with hardeners. The F-5 formula uses boric acid (like the modern F-5), and the F-1 (just sodium thiosulfate) had a hardening addition: either Kodak Liquid Hardener, or a sulfite/acetic acid/alum mixture.
I am completely open to being educated as to the longevity and emulsion hardness of those old photos. I am ignorant of photo processes and materials of that period.
William, You are probably right about plain water being sufficient for resoaking the prints. I just figured that adding a wetting agent would be kinder to the emulsions.
In addition you've got a certain survior bias. Any of the photographs that didn't last got tossed before now. So what you're looking at isn't likely to be a real sample of what 80 year old pictures are like.
Reminds me of those who argue they don't trust RC because it hasn't been used for 100 years. Then go on to point to a 100 year old fiber print trying to prove all of todays fibre prints will last 100 years.
The only real conclusion you can draw is that those photographs have lasted until today. How much is really related to us today? Don't know but I'm doubtfull. Unless you're using the same paper,chemicals and process.
There are many documented problems with image longevity with RC papers. One of the first problems was the plastic coating delaminating from the paper base. The manufacturers have worked to correct that problem, but there are still problems with the images changing even when treated with Sistan or selenium toner. See Ctein's darkroom book on his problems with RC paper and subsequent tests to determine the causes. I don't know whether the manufacturers have solved the image stability problems documented by Ctein, although I'm sure they have worked on them.
I would suspect that you could better trust a fiber based paper to last longer than an RC print at this point as the paper formulations required for archival permanence are well known as are the processing requirements of the image itself. The RC papers have problems with the plastics breaking down from UV light - that's a tough one to cure with any type of clear plastic.
Personally, I would be equally suspect of the optical brightners that have been added as they too react to UV light. How long do they last, and what are the bye-products produced when they start to break down?
As for hardeners, I am not sure they add to the longevity of the print in any other way other than making the emulsion tougher and more abrasion resistant. Part of what the hardener does is cause the gelatin molecules to cross-link (polymerize) which strengthens the gelatin making it less susceptible to physical damage from handling, and swell less in the presence of humidity.