[pure-silver] Re: Sea Water Washing and Journal of the SMPE
- From: "bobkiss @caribsurf.com" <bobkiss@xxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Sun, 3 Aug 2014 19:08:57 -0400
DEAR RICHARD,
Thanks for posting that. I had the pleasure of hearing Dr. James
lecture on this topic after we read about it in his book. I recall that we
found it entertaining that, after all of the high level photo chem we had
to learn, that sea water would to a very good job washing prints and film
if followed by a fresh water wash.
***Perhaps the pain killers are making me inept but I can't seem to find
the SMPTE journal on the site you recommended. It is an amazing site & I
would love to download some of the journals but my search on the site does
not lead me to them.
On Sun, Aug 3, 2014 at 2:25 AM, Richard Knoppow <1oldlens1@xxxxxxxxxxxxx>
wrote:
> First of all, I have discovered (probably lots of you knew already)
> that a fairly complete collection of the Journal of the Society of Motion
> Picture Engineers (later the Society of Motion Picture and Television
> Engineers) and also many of the earlier "Transactions of the SMPE" are
> available at http://www.archive.org These are free downloads. This
> site has a treasure of other stuff on it including old radio programs and
> many technical journals.
> I made an interesting discovery while re-reading a paper on sea water
> washing
> "Sea Water Washing" Eaton and Crabtree (of Kodak Research Labs) JSMPE
> V.VXL, June 1943 p.380 et seq. The research was done because of the
> limitations of availability of fresh water at many military installations
> such as ships at sea that nonetheless had to process film and prints. In
> this research Eaton and Crabtree discovered that sea water washing was
> considerably more efficient than fresh water washing and the results
> permanent providing the sea water wash was followed by a short fresh water
> wash. It was this research that inspired the later research that resulted
> in the development of Kodak Hypo Clearing Agent and the discovery that
> sulfites were even more effective that sea water in accelerating washing.
> It was later discovered by T.H.James, also of Kodak Research Labs, that
> excessive washing resulted in a loss of image stability. This was such
> heresy that James was reluctant to publish his results until similar
> research was published by a researcher at Fuji labs. It turns out that a
> slight amount of thiosulfate remaining in the emulsion stabilizes the image
> silver. Not as well as toning with a sulfiding toner or selemium or gold
> toners but considerably. Now, what caught my eye in reading Eaton and
> Crabtree is that they _discovered the same thing_! It was not followed up
> but they were able to wash both film and paper prints completely free of
> residual thiosulfate in their tests and found on accelerated aging that the
> images faded much faster than when some residual thiosulfate remained.
> They remark only that they thought the thiosulfate reacted with the silver
> to produce something more stable than if the thiosulfate was completely
> removed. This was in 1943 and the effect was not re-discovered for
> something like ten or more years.
> About the same time as the sea water washing was being researched
> Crabtree, et.al. published the paper showing the result of an ammonia and
> peroxide hypo eliminator. This eliminator has not been recommended for
> general use for many years for several reasons, one being its too complete
> removal of thiosufate (especially if some idodide is added). This paper is
> also in the JSMPE.
> I strongly recommend this site for anyone interested in researching the
> history of photography especially as it was practiced in the professional
> motion picture industry.
> FWIW, the washing recommendations provided by Kodak for KHCA take into
> account the problem of overwashing. KHCA is now discontinued but an
> essentially identical product is made by Ilford.
>
>
> --
> Richard Knoppow
> Los Angeles
> WB6KBL
> dickburk@xxxxxxxxxxxxx
> ============================================================
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