[alt-photo] Re: Gum solution help needed

[Loris Medici]

  FWIW, formalin indeed preserve the gum solution, BUT, you have to use 
it up relatively quickly: Formalin will evaporate slowly, to the point 
of not being able to protect your solution - especially true in case 
there's a little remainder solution in a large container. At least 
that's my experience...

Therefore, my preference is towards dry / soluble preservators. I 
personally use sodium benzoate, but aspirin looks definitely very 
interesting - especially for people who don't want to purchase / stock 
an extra chemical (such as thymol + alcohol or sodium benzoate or the 
dangerous mercuric chloride) in order to preserve their gum solutions. 
(E.g. students, workshop participants et. al. ...)

Thanks Philippe.

Regards,
Loris.


08.08.2010 15:35, John Brewer yazmış:
> I use 15ml formaldehyde to 1 litre of gum.
>
> J.
>
> -----Original Message-----
> From: alt-photo-process-list-bounces at lists.altphotolist.org
> [mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On Behalf Of
> henk thijs
> Sent: 08 August 2010 13:29
> To: The alternative photographic processes mailing list
> Subject: [alt-photo] Re: Gum solution help needed
>
> Just wondering about Philippes suggestion: an aspirine i.s.o. formaldehyde
> or equivalent.
> If so, how much? Is one 500 mg tablet enough for one liter gum?