[pure-silver] Re: Toning formulas
- From: Ryuji Suzuki <rs@xxxxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx, pgauth@xxxxxxx
- Date: Tue, 25 Apr 2006 15:32:46 -0400 (EDT)
It's easy to fog a piece of undeveloped paper if you expose it to the
fume coming out of the tray for a few moments and then develop normally.
Exposure to H2S gas creates silver sulfide cluster on silver halide
surfrace and when this is large the crystal is developable. It doesn't
take many molecules on each crystal to render the crystal developable.
From: Philippe Gauthier <pgauth@xxxxxxx>
Subject: [pure-silver] Re: Toning formulas
Date: Tue, 25 Apr 2006 16:00:55 -0400
> Tim Rudman a écrit :
>
> >A word of warning Jim
> >Sodium sulphide toning releases a 'rotten egg' smell - the gas responsible
> >is a potent fogger for sensitised emulsion. Best to do it away from your
> >darkroom or film/paper storage areas.
> >
> >
> This is probably true in theory, but in practice, I never noticed any
> fogging. But I rarely mix more than 5 or 10 grams of sodium sulfide at a
> time. It really cannot produce that much sulfide gas... I think that if
> you don't produce enough gas to kill yourself, the chances that the
> paper will be noticeably fogged are slim unless the place is very badly
> ventilated and you mix a lot of sodium sulfide all the time.
>
> PG
>
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