[Alt-photo] Sodium Thiocyanate For Fixing Out Lumens

Jacques Kevers jacqueskv at gmail.com
Fri Aug 18 00:37:00 UTC 2017


Marek & all,
I have these 2 copies. The xeroxes are quite bad, however. I just improved
the first in a quite decent pdf. Second will follow, but I need some time.
Whoever is interested, pls drop me a note at jacqueskv at gmail.com
Best,
Jacques

Jacques Kevers
Beau Site
Première Avenue 7
B-1330 Rixensart
Belgium
+32 2 653 56 02

2017-08-17 20:02 GMT+02:00 Marek Matusz via Alt-photo-process-list <
alt-photo-process-list at lists.altphotolist.org>:

> I would be very interested in the two articles on the chemistry of fixing.
> Could somebody share a copy?
> Marek
>
> Sent from my iPhone
>
> > On Aug 15, 2017, at 12:51 PM, Ryuji Suzuki via Alt-photo-process-list <
> alt-photo-process-list at lists.altphotolist.org> wrote:
> >
> > You might want to get a copy of this paper if you like to see what's
> known in situations that are somewhat close to what you are doing. Without
> chemical development process you don't have filaments but you can probably
> learn from what happens to the smallest grain, thinnest filament condition
> among what he studied. Abstract is from uncorrected OCR, sorry about some
> errors.
> >
> > The Stability of Silver Filaments
> > T. H. JAMES, Research Laboratories, Eastman Kodak Company, Roch:ester,
> N. Y. 14650
> >
> > PHOTOGRAPHIC SCIENCE AND ENGINEERING Volume 9, Number 2, March-April 1965
> >
> > The effeds on the strudure of the developed silver of storage at high'
> humidity and of treatment with various salt solutions were studied on
> several bromide emulsions. An over-all increase iii transmission density,
> with some decrease in refledion density, occurred with fine-grain emulsions
> within a few hours upon storage at approximately 100% relative humidity at
> 21°C. Similar changes occurred more rapidly at higher temperatures. 'The
> changes were more pronounced with unfixed, fully developed film than with
> fixed film, and the changes in density wete accom- panied by a thickening
> and breaking up of the filamentary strudure and an increase in crystal-
> lite size. Similar changes in filament strudure, and a decrease in
> refledion density, occurred for all chloride, chlorobromide, arid bromide
> emulsions tested, but IiHle or no change in trans- mission density was
> observed when the original silver halide grain size exceeded about 0.4 ",.
> Iodide, whether derived from the processing solutions or from the
> development or fixation of the silver halide grains, retarded the changes.
> A rapid conversion of filaments into nonfilamentary, rounded particles
> occurred in the chloride, chlorobr9mide, and bromide emulsions when the
> unflxed, developed film was immersed in a 1%or stronger.solution of a
> thiocyanate or chloride. The degradation of the fllaments was retarded by
> iodide and thiosulfate, by the presence of strong reducing agents, or by
> stringent exclusion of oxygen, but it did occur readily under the
> > laHer condition when silver ions were added to the solution. The
> degradation of the fllaments appeared to be a recrystallization phenomenon,
> and a mechanism based on local cell action was suggested.
> >
> >
> > Regarding the fixing mechanism of sodium v ammonium thiosulfate, and
> thiocyanate, see
> >
> > The chemistry of fixing I. Silver complexation by thiosulfate anion
> > M.R.V. Sahyun, Imaging Research Laboratory, 3M Company, St. Paul,
> Minnesota 55101
> > PHOTOGRAPHIC SCIENCE AND ENGINEERING· Volume 17. Number 2. March/April
> 1973 Reprint Number 7326
> >
> > The chemistry of fixing II. Silver complexation by thiocyanate anion
> > M.R.V. Sahyun, Imaging Research Laboratory, 3M Company, St. Paul,
> Minnesota 55101
> > PHOTOGRAPHIC SCIENCE AND ENGINEERING. Volume 17. Number 2. March/April
> 1973 Reprint Number 7327
> >
> > Chapter 5 of James's 1977 book is also an excellent reference. (The
> chapter written by R. W. Henn)
> >
> > Finally, be careful about thiocyanate as a fixing agent. As James's
> paper shows, it can change the morphology of the silver image, and you want
> to control the residue very carefully. Also, strong thiocyanate solution
> damages gelatin and weakens the mechanical properties and perhaps long term
> durability. I think it is probably wise to formulate a fixing solution that
> is primarily based on thiosulfate but uses a pre-bath or an additive to
> alter the image tone as desired. The topic of image tone was a very common
> one for the radiographic film emulsions and their developer formulation.
> Very numerous patents issued, with very many compounds named (but in
> reality, I bet only a few used in practice).
> >
> > Ryuji Suzuki
> > "Don't play what's there, play what's not there" (Miles Davis)
> >
> >> On 14 Aug 2017, at 14:00, Andy Duncan via Alt-photo-process-list wrote:
> >>
> >> Hi all,
> >>
> >> I’m experimenting with different ways of fixing lumen prints, and read
> >> somewhere (I think in a thread on apug.org) that sodium thiocyanate
> can be
> >> used to fix out prints. I've used Ilford Rapid Fix in the past, but my
> main
> >> fixer in recent years has been TF-4 from Photo Formulary, which is what
> I
> >> use for my film. The color shifts from both were pretty similar, both
> being
> >> ammonium thiosulfate. I began using the sodium thiocyanate recently, and
> >> after my last batch of prints, I noticed that after processing, some of
> the
> >> prints continued to darken. I processed in a 5% dilution for 1-2
> minutes (I
> >> don't get real scientifically accurate with my times when processing
> >> lumens...maybe that's part of my problem); the source I first read that
> >> mentioned using sodium thiocyanate gave a 10% dilution. So my question
> is
> >> this: is sodium thiocyanate as permanent of a fixer as the other fixing
> >> agents in TF-4 and Ilford Rapid Fix?
> >>
> >> I was also wondering if any of the chemists out there could explain in
> >> layman's terms the difference between sodium thiocyanate and ammonium
> >> thiosulfate? What is the effect each has on image permanence and
> >> stabilization?
> >>
> >> I suppose I should add that I'm not afraid of the color shifts that
> occur
> >> after fixing a lumen print, nor are they unwanted. On the contrary, I
> tend
> >> to welcome them. I just want the lumen to be as permanent as I can make
> it.
> >> I'm starting to prefer the shifts that occur with the sodium thiocyanate
> >> over those that occur with TF-4, so I'd like to make sure they'll be as
> >> stable when processed in TF-4. I have prints that are 10+ years old that
> >> have had no further shift in color/intensity/brightness after being
> hung on
> >> my walls. These recent ones shifted only hours after being taken off my
> >> drying racks.
> >>
> >> Thanks in advance!
> >> Andy
> >> _______________________________________________
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