[alt-photo] Re: Chlorox Bleach Development of Gum

[Loris Medici]

Thanks for the insight. I haven't tried any other alkaline compound
with gum but I know ammonia is useful for trigger/accelerate
development in casein + was once advised for stubborn gum layers too,
so I think you're on the right track. OTOH, bleach is easy to find
(household item), plus, we don't use it that much; only about 20 -
40ml per liter. And, a final metabisulfite clearing bath will take
care of the bleach remaining in the paper - if any - later...

Regards,
Loris.

2010/1/13  <pfriedrichsen at sympatico.ca>:
>
> Has anyone tried using an alkaline bath instead of the bleach?.
>
> I haven't tried the bleach development but I have been working with "gum"
> subing gelatine, or casein, and the print clears more readily as the
> developer is made more alkaline. Salts I use are Sodium Bicarbonate for a
> mild alkaline  solution pH of about 8, or Sodium Carbonate with a solution
> pH of around 10.
>
> A dilute bleach solution that I made up using about 200 ml water to 20 ml
> household bleach gave me a pH of 11.2. This is very alkaline. From what I
> understand, an alkaline pH changes the charge of particles and cellulose, so
> they start to repel each other hence the alkalinity of most detergents.
>
> This would be good because it would avoid the use of hypochlorite which is
> hard on cellulose fibers. This is just a hunch.