> I was wondering...
>
> If I premixed my platinum and palladium with my ferric oxalate solution,
> and I kept it in a nice dark brown bottle, in a nice dark place. How
> long will it last before "changes" begin to occur?
>
> David
>
David, when I worked as a photochemist for Sprint, we experimented with
combining all three for sale in a platinum kit. We found that when mixed
together it would last about six months if the bottle was unopened.
After leaving Sprint and Rhode Island and moving to New Mexico, I found
myself in the situation of needing to make a print RIGHT NOW and not
having any decent ferric oxalate, so I tried an old bottle of sensitizer
from the Sprint Days, which was nine years old. It showed a little fog
straight out of the bottle, but a little peroxide in the sensitizer
"Cleared things up". Granted this is an isolated incident, but since
this experience related to your question, and pertained clearly to
alt-photo, I wanted to relate it.
John