[pure-silver] Re: Old Paper Developer Question

 Hi Bogdan,

Make a stock of 1% benzatriazole in isopropanol and start with adding 5-10 ml 
per liter developer.

Best,

Cor

> -----Original Message-----
> From: pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-
> bounce@xxxxxxxxxxxxx] On Behalf Of Bogdan Karasek
> Sent: dinsdag 19 februari 2008 2:27
> To: pure-silver@xxxxxxxxxxxxx
> Subject: [pure-silver] Re: Old Paper Developer Question
> 
> Hi,
> 
> Off hand, how much Benzotriazole should be added to Dektol to prevent
> fogging.  Several months ago, I was given some old printing paper by my
> neighbor prior to his return to Switzerland.   He had kept it in a dry
> place for at least 20 years.
> 
> What would be a good ballpark figure for adding Benzotriazole to Dektol,
> in order to get me started and I can experiment from there.
> 
> How many grams per litre of 1:2 Dektol?
> 
> Cheers,
> Bogdan
> 
> Richard Knoppow wrote:
> 
> >
> > ----- Original Message ----- From: "Don Sweet" <don@xxxxxxxxxxxxxxxx>
> > To: <pure-silver@xxxxxxxxxxxxx>
> > Sent: Sunday, February 17, 2008 9:13 PM
> > Subject: [pure-silver] Old Paper Developer Question
> >
> >
> > I have few boxes of 25+ year old enlarging paper, including Ilfobrom and
> > Portriga Rapid.  It is unopened, so I decided before blazing away I
> > should look for some information about how to best to process it,
> > particularly to minimise fog. First I sourced some benzotriazole which I
> > thought could just be added to Dektol or Neutol or Bromophen developer.
> >
> > Then following links from the UnblinkingEye website I found some
> > suggestions that both amidol-based or glycin-based developers are more
> > resistant to fog than the usual MQ or PQ blends.  Does anyone know if
> > that is right, and whether either of them is likely to be a better
> > developer for my old paper?
> >
> > Thanks
> > Don Sweet
> >
> >    The fog in old paper or film comes from a chemical change in the
> > emulsion. I think the advice about Glycin or Amidol may come from some
> > confusion about the type of fog here. Some developers are less likely to
> > cause fog themselves than others and don't need as much anti-fog.
> > However, this is also dependant on pH. Some low activity film
> > developers, like D-76 and D-23 don't produce enough fogging to require
> > an antifoggant although fresh D-76 will produce a slight amount of fog.
> > Higher pH developers of the sort usually used for print developing
> > nearly always need some anti-foggant. This is also because fog is not
> > tolerable in prints but can be tollerated in film if not too great.
> >    Benzotriazole is more effective in reducing fog in old paper than
> > bromide although bromide often works. Benzotriazole also tends to
> > produce cold images where bromide tends to warm them up. Usually
> > benzotriazle will result in less loss of speed.
> >    Grant Haist has a chart in his book showing approximate amounts of a
> > benzotriazole solution to add to developers for different amounts of
> > fog. Be aware than if the fog is bad enough no anti-foggant can fix it.
> > Also, the antifoggant will affect the paper curve a bit so it won't look
> > quite the same.
> >    Plain Dektol or Bromophen or any other standard paper developer works
> > fine with this stuff.
> >    Unfortunately, my copy of Haists' book is boxed up at the moment.
> >
> > ---
> > Richard Knoppow
> > Los Angeles, CA, USA
> > dickburk@xxxxxxxxxxxxx
> >
> >
> >
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> >
> 
> --
> ________________________________________________________________
>    Bogdan Karasek
>    Montréal, Québec                     bogdan@xxxxxxxxxxxxxxx
>    Canada                               www.bogdanphoto.com
> 
>                       "I bear witness"
> ________________________________________________________________
> 
> 
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