[pure-silver] Re: AZO and Benzotriazole for anti-fogging

  • From: BertS <aasainz@xxxxxxxxxxxxx>
  • To: pure-silver@xxxxxxxxxxxxx
  • Date: Wed, 20 May 2009 22:37:17 -0400

Richard Knoppow wrote:

----- Original Message ----- From: "BertS" <aasainz@xxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Wednesday, May 20, 2009 3:45 PM
Subject: [pure-silver] Re: AZO and Benzotriazole for anti-fogging

Bogdan Karasek wrote:

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.


Here is something I found in my archives. Source is Richard Knoppow, of course.


"Alfred Lorona" <w6wqc@xxxxxxxxxxxxxx> wrote in message
> >
> > Are benzotriazole pills available anywhere?
> >
> >
  AFAIK no longer. Kodak put this up as Antifog NO.1
(Antifog No.2 was 6-Nitrobenzimidazole nitrate).
Benzotriazole is available as a powder. For use make it into
a 0.2% stock solution. At this low concentration it will
dissolve in water.
 For fog suppression of outdated material the stock is added
to developer from 20 ml/liter to 40ml/liter for film, and
from 50ml/liter to 500 ml/liter for paper.

Richard Knoppow
Los Angeles, CA, USA


Thank you Bert, as usual my references are tucked away in boxes. Eventually I must fix this but it takes other people now because of my back.

Richard Knoppow
Los Angeles, CA, USA

My pleasure to be of help. I keep stuff worth holding to in a subdirectory labeled simply "Knoppow." ;-)

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