[pure-silver] Re: AZO and Benzotriazole for anti-fogging
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Wed, 20 May 2009 15:52:43 -0700
----- Original Message -----
From: "Bogdan Karasek" <bkarasek@xxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Wednesday, May 20, 2009 3:20 PM
Subject: [pure-silver] AZO and Benzotriazole for
anti-fogging
Hello,
I want to do some contact printing using AZO paper that
has been kept in a fridge for the past ten years. I'll be
using it for the first time tomorrow. If there is
fogging, how much benzotriazole should I add per liter of
Dektol 1:2. The "Darkroom Cookbook" says that
Benzotriazole does not dissolve readily in cold water. It
says to dissolve in hot water ... 125°F/51.67°C or higher.
Should I heat up the water before diluting the Dektol or
can the Dektol dilute solution be heated up and then
adding the Benzotriazole?
Any and all recommendations are welcome.
Cheers,
Bogdan
Make up a solution of 1:200 (0.2%) Benzotrizole using
hot water. Then use this as part of the water used to make
up the working solution of Dektol.
There is a chart in Grant Haist's book _Modern
Photographic Processing_ but I don't know where my copy is.
This book was originally published by John Wiley and sons
but went out of print and was republished by the author. I
don't know if Grant is still alive but he sold the books
himself. Not cheap but about the same as current technical
books of similar size. You may be able to find a copy
throught your library or Amazon. Watch out for photocopies,
Grant's republished edition was newley printed. Amazon has
it listed at $125 which is a good price.
Benzotriazole is difficult to dissolve in water but
will dissolve in isopropyl alcohol. For as dilute a
concentration as the above adding some rubbing alcohol to
the water will help if the stuff is resistant. Haist is a
much better source than Anchell.
--
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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