[pure-silver] Re: Potassium Bromide and chlorhydroquinone
- From: Don Sweet <don@xxxxxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Wed, 09 Apr 2008 14:51:58 +1200
A few weeks ago there was a discussion on this list about the possible use
of chlorhydroquinone as an anti-fogging developer for old paper, if only you
could find some. Since then I have found there is a recipe for "Maxim
Muir's Chlorhydroquinone-Substitute Developer" on page 174 of Carson Graves'
book The Elements of Black and White Printing (2ed), which provides a
work-around for the chlorhydroquinone shortage if anyone is interested.
Don Sweet
----- Original Message -----
From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Wednesday, April 09, 2008 2:19 PM
Subject: [pure-silver] Re: Potassium Bromide
>
> ----- Original Message -----
> From: "Dennis Purdy" <dlp4777@xxxxxxxxxxxxx>
> To: <pure-silver@xxxxxxxxxxxxx>
> Sent: Tuesday, April 08, 2008 5:35 PM
> Subject: [pure-silver] Re: Potassium Bromide
>
>
> I have some that is the same as yours. Old and chunky or
> solid and I
> just chop it up and use it and it works fine. Though I am
> not sure it
> will do you much good saving old fogged paper. I think you
> need anti
> fog #1 or (benzotriazole).
> Dennis
> On Apr 8, 2008, at 16:36, mmagid3005@xxxxxxx wrote:
>
> I don't know for certain about the Kbr but think it has
> just absorbed some moisture.
> Kbr is not as effective an anti-foggant as benzotriazole
> but is worth trying since you have it. Quite a lot can be
> added to the developer but beyond perhaps 5 grams/liter it
> will begin to cause a speed loss. Ira Currant, who was
> Ansco's expert on toning, has a patent for developers for
> cold sepia toning which contain huge amounts of bromide.
> While bromide is usually recommended for getting warm tones
> on paper and warmer toned images Currant discovered that in
> very large amounts it resulted in colder sepia tones. The
> developer examples shown in the patent were similar to
> standard Ansco print developers, one substantially the same
> as Dektol. He used bromide up to 50 grams per liter. The
> relevance here is that large amounts of bromide are OK but
> exposure will have to be increased.
> I suggest cutting a sheet into test strips and seeing
> how much fog is produced with varying amounts of bromide.
> Fix out a bit without any exposure or development to get a
> comparison.
> In general benzotriazole has greater anti-fog effect
> with less speed loss. The latent image centers from chemical
> fogging and from light are somewhat different so its
> possible to suppress the fog without destroying the low
> level latent image, at least not completely.
> Let us know your results.
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@xxxxxxxxxxxxx
>
>
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