Re: hp and pot di with pt/pd

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From: Manuel Gomes Teixeira (punctumgt@netvisao.pt)
Date: 04/10/03-09:12:01 AM Z


Carl,

Thanks for your reply .

For how long will 1% potassium chlorate last in a closed dropper bottle
before will go bad ?

I agree with you concerning the use of contrasting agent. Less is More in
this case. I always try to make my negatives with the adequate contrast for
the process. But even considering that FOx, Pt&Pd are in perfect
conditions and the negative is in good shape do you get prints absent of
any fog whithout using any amount of Contrast agent ?

Manuel
> From: Carl Weese <cweese@earthlink.net>
> Reply-To: alt-photo-process-l@sask.usask.ca
> Date: Thu, 10 Apr 2003 06:58:23 -0400
> To: alt-photo-process-l@sask.usask.ca
> Subject: Re: hp and pot di with pt/pd
>
> Manuel,
>
> It works quite well. Very dilute potassium chlorate or ammonium dichromate
> used as an additive can be preferable to an apporach with A and B ferric
> bottles. In fact this is recommended in "The New Platinum Print" on page 57.
> One drop of 1% makes a significant contrast boost in an 8x10. I prefer to
> make negatives that need no contrasting agent at all, but when necessary I
> do it this way. The "B" bottle of ferric would go bad before I'd used three
> drops.
>
> ---Carl
> --
> Web site with picture galleries
>
> and workshop information
>
> http://www.carlweese.com
>
>> From: Manuel Gomes Teixeira <punctumgt@netvisao.pt>
>> Reply-To: alt-photo-process-l@sask.usask.ca
>> Date: Thu, 10 Apr 2003 00:40:20 +0100
>> To: alt-photo-process-l@sask.usask.ca
>> Subject: Re: hp and pot di with pt/pd
>>
>> Why in all Pt/Pd literature is never advised to use Potassium Chlorate
>> solution added to the sensitiser as H2O2 and instead is added previously to
>> the Ferric Oxalate solution ? Is there any chemical explanation for that ?
>
>


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