Thank you, Richard. I knew I was missing a big part of the story. Now
it appears that my older prints may survive, since I couldn't be
bothered saving hypo and was too impatient for more than a 45-50 minute
wash of my prints. Laziness may breed longevity...
-Bill
On Tuesday, June 21, 2005, at 01:20 AM, Richard Knoppow wrote:
-----Original Message----- From: Bill Stephenson <photographica@xxxxxxxxxxx> Sent: Jun 20, 2005 9:22 PM To: pure-silver@xxxxxxxxxxxxx Subject: [pure-silver] Re: Cleaning Drying Screens
Was Sistan (or its equivalent) available to Cunningham, Steichen, Weston, Adams, and the rest of the crowd making prints before WWII? If not, how have their prints survived? (This question is kind of along the lines of "why are we - and our kids - alive? we didn't have seatbelts and child seats when we were kids".)
-Bill
It wasn't. Not all prints of the period have survived well. I can't speak about Imogene Cunningham's prints but Weston's were notorious for being short lived. Partly this is because he didn't believe the low capacity Kodak gave for fixer.
There is something else operating here. About 45 years ago T.H. James, of Kodak Research Labs, discovered that a trace of hypo remaining in the emulsion would protect the image against oxidation. He was reluctant to publish because it was virtual heresy, however, researchers at Fuji discovered the same thing shortly after and did publish. This finding caused Kodak and others to completely revise their recommended processing procedures for film and especially prints. Previous to this Kodak was recommending the use of Hypo Eliminator or very long washes. Not after. Kodak even became slightly nervous about recommending the use of sulfite wash aid. The rather short washes currently recommended for film and paper are the result of these findings. What this means is that prints which were properly fixed but did not get more than a routine washing were more stable than those that were processed to what was considered archival standards fifty years ago. If _all_ the hypo is washed out, and the print is not toned, it is much more vulnerable to oxidation and sulfiding from atmospheric polutants or impurities in the mounts than those with a little hypo left in them.
Probably the mechanism is that the hypo causes a layer of sulfide to form on the silver crystals. Once that happens the crystals are substantially protected against more sulfiding or oxidation. If there is too much hypo, of course, it will attack the image and cause staining and image fading. So, sloppily processed prints did not survive bu those receiving competent _normal_ but not archival washing survive very well. I think this is also the reason so many drugstore photofinisher snapshots survive in pristine condition. Of course, those processed with exhausted fixer and rushed washes are a mess but it seems to me that the majority of snapshots from the 20s and later have survived pretty well.
Ironically, the sort of multiple hour washes and long soaks recommended by Ansel Adams and others at one point are pretty good ways of shortening the life of a print.
--
Richard Knoppow
dickburk@xxxxxxxxxxxxx
Los Angeles, CA, USA
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