From: Richard Knoppow (dickburk@ix.netcom.com)
Date: 07/09/01-12:46:43 PM Z
At 09:57 AM 07/09/2001 -0700, you wrote:
>The untoned salted paper picture is very fragile. You have raw silver
>halides in direct contact with the environment. An option would be to
>laquer the print to seal out the air. I do not know how this will effect the
>long term image stability. Although I have seen some salt prints from the
>1860's that were laquered and they still looked pretty good. The color
>change in a photo image is the result of changes in the crystalin strucure
>of the image forming grains and how they reflect light. Be very carefull
>with selenium, the image can bleach very quickly depending on the paper you
>use. I do not recommend selenium, but if you want to give it a try, use no
>more than 1/8 teaspoon selenium toner to one liter of water. No more time
>than 2 minutes.
>
>your mileage may vary.
>
>Joe Portale
>Tucson, AZ
>
I wonder if a stabilizer like Agfa Sistan might be effective. Sistan
consists of a very weak solution of thiocyanate. Its not as effective a
protection for conventional silver images as toners but does give some
protection. However, Thiocyanate is a silver solvent so it may have
reducing effects on the image similar to that from the ammonium thiosulfate
in KRST.
If the salt prints are properly fixed and washed there should be no
halide left in them. The color of the untoned image suggests that the image
silver is extremely finely devided, which would make it more suseptible to
oxidation from atmospheric polutants. Gold toning is very effective against
this provided the conversion is great enough
Other possibilities are Kodak PolyToner, a combination of a sulfide toner
and Selenium, and Kodak Brown Toner, a polysulfide toner. Agfa Viradon is
similar to PolyToner. Brown Toner has no silver solvents in it. I have no
idea what color any of these would produce on salted paper. Brown Toner
tends to produce bluish images on microfilm although its a "sepia" toner.
Another possibility is the Borax based polysulfide toner devised by IPI
for microfilm protection. Its similar to Kodak Brown Toner but doesn't have
the "rotten egg" odor. Again, I have no idea of the image color it will
produce. The objective for microfilm was to leave the image color unchanged.
The stuff is not hard to make but must be made up accurately to get the
right sort of polysulfide molecules. I will post the instructions if its
desired.
Its hard to guess at the permanence of salt. There is no gelatin carrier
or gelatin undercoating (baryta) as in conventional papers, both will have
some effect.
Presumably the paper will have a considerable effect.
>
> ----- Original Message -----
>From: "Andre Fuhrmann" <Andre.Fuhrmann@uni-konstanz.de>
>To: <alt-photo-process-l@sask.usask.ca>
>Sent: Monday, July 09, 2001 7:49 AM
>Subject: Re: archival salt prints
>
>
>>At present I never toned my salt prints because I like their
>>characteristic reddish-brown colour, also if I know that without
>>gold toning they are not archival.
>>Now I am planning a new number of salt prints, and I would ask if
>>there is the way to achieve a better stability while retaining their
>>original colour.
>>Is there any experience in this matter?
>>
>>Alberto
>
>I also happen to like the rusty colour of untoned salt prints. Being
>archival is, of course a matter of degree. Frankly, I do not know
>how unstable untoned salt prints really are. From the fact that
>virtually all known salt prints of the classical period are toned one
>should by no means infer that the reason for toning was to achieve
>greater permanence. I have a sizeable collection of pre 20s
>photographic literature. The authors when giving recipes for toning
>_never_ discuss archival matters but only image colour. The rusty
>tone of "raw" salt prints was simply not approved of in those days.
>Of course, toning can improve permanence -- in particular, gold
>toning certainly does. But this is not to imply that untoned prints
>have no reasonable life expectancy. A necessary condition for
>reasonable stability is, of course, careful processing and storage.
>
>Instead of gold chloride you may want to try toning with selenium.
>At a dilution of 1 + 99 (e.g. Kodak Rapid Selenium Toner) you can
>tone for about 2 minutes without loosing too much density. The
>resulting image tone is somewhat closer to the raw tone than with
>gold chloride toner. But I do not know whether a toning bath at that
>dilution and for such a short time can enhance permanence.
>
>André
>
>
>
---- Richard Knoppow Los Angeles,Ca. dickburk@ix.netcom.com
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