[alt-photo] Re: Alternative sensitiser

[sam wang]

Peter,

For years I was searching for a source for ammonium caseinate, which
according to Franklin, should dissolve readily in water - he used what his
research lab provided him. But all I could find was sodium caseinate, which
took some time to dissolve but worked quite well otherwise and eliminated
the need to produce the casein from skim milk each time. Will have to see if
it still needs pH adjustment, but won't be able to do that till I get back
home in a few weeks.

Thanks again for all the information.

Sam Wang


I use a 5% casein solution made from skim milk/vinegar. It is dissolved with
> a small amount of sodium bicarbonate to get it into solution. I make sure
> the final pH is around 7.
>
> The peroxide needed is very dilute (0.1%) If you go above 3% the print
> actually will not develop as well, and it wastes a lot. ) 0.1-1% range is
> good. You can add a small bit of ammonia to help with dissolving the
> emulsion (as you know).
>
> I use a 1:1 casein/sensitizer ratio.
>
> I hope this will help.
>
> Peter Friedrichsen
>
>