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

[Loris Medici]

Just noticed: I guess sodium bicarbonate also is a household item,
plain simple baking soda right? ;) It's worth a try...

2010/1/13 Loris Medici <mail at loris.medici.name>:
> 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.