Desensitising


Liam Lawless (lawless@vignette.freeserve.co.uk)
Sun, 31 Jan 1999 00:13:19 +0000


Hi Judy,

Silver iodide has density, yes - maybe less than silver, but my point is
that you won't have three-quarters of the image disappear in the fix, even
if it's printing density does not exactly correspond with its visual
density. You've no doubt seen Sandy's caution, but if you don't leave them
on the window sill maybe you'll get a couple of shots at printing negs that
are otherwise useless. I honestly don't know how well it'll work, but why
not try?

The desensitiser I mentioned was, apparently, believed to be 4% pot. iodide,
so that is what I'd use. Probably, though, the strength isn't very
important.

Has anyone out there tried desensitising? I tried with phenosafranine once,
but I don't think it works with most modern emulsions.

Liam

-----Original Message-----
From: Judy Seigel <jseigel@panix.com>
To: alt-photo-process-l@sask.usask.ca <alt-photo-process-l@sask.usask.ca>
Date: 30 January 1999 03:55
Subject: Re: Amidol Redeveloper

>
>
>On Fri, 29 Jan 1999, Liam Lawless wrote:
>
>>
>> I have a suggestion re. your problem anticipating how much density will
be
>> removed by fixing a partly-redeveloped neg. As I'm sure you've observed,
>> silver iodide is relatively inert and takes ages to tone or redevelop.
It's
>> also pretty light stable as long as it doesn't get too much exposure to
>> sunshine. I have read that putting an unfixed print or neg into pot.
iodide
>> solution converts any silver chloride or bromide into silver iodide; I've
>> done this in different contexts and am sure it's true; indeed I remember
>> reading in a very old book that some commercial desensitiser (German, I
>> think it was) was thought to be a 4% solution of pot. iodide,
>>
>> My idea is basically that if, instead of fixing your neg when it appears
>> right you stick it in pot. iodide, no significant density change will
occur,
>> and the result will be sufficiently stable on camera negs that are filed
>> away in cabinets or ring binders. If necessary, they can always be fully
>> redeveloped at a later date, to bring you back where you started. Worth
a
>> try if you have negs that are unprintable anyway.
>
>
>You mean the silver iodide wouldn't have density? Ye gods Liam -- that's
>either daft or brilliant... both, maybe. What % K iodide would you use?
>
>Judy
>
>



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