U of S | Mailing List Archive | alt-photo-process-l | Re: Potentially stupid pt/pd question

Re: Potentially stupid pt/pd question


Thanks for clearing that up (no pun intended); that makes a lot of sense.

I'm not sure about the pH of the water here, although I've never had
problems clearing before.

I think saturated developer is a more likely scenario.  It's not that old,
but I admit I have let it go longer than normal without replenishing it. 
I've got a shipment of potassium oxalate on the way, so I'll add to what
I've been using and see if that helps.

Camden Hardy


> Potassium oxalate developer by itself won't stain paper. What is
> probably going on is that your developer is absolutely saturated with
> ferric oxalate from that it is removing from the print. So when you
> put the print into the tray of developer, it is bathing in a
> concentrated sea of ferric oxalate in solution. I would be willing to
> bet that 1) your developer is old and saturated with ferric oxalate
> and has a pH at or above 7.0, and 2) your rinse water is slightly
> basic as well. This would explain the staining on both sides of your
> paper. So it most likely IS a clearing issue, IMO, that you are
> seeing, only you are doubling down by soaking your paper in a
> developer loaded up in ferric oxalate removed from all your previous
> prints.
>> Clay, I definitely tell you it's not the ferric that's staining,
>> although
>> it is the same color (which is why I initially thought it was a
>> clearing
>> issue).
>> The entire sheet of paper is stained (front and back), not just
>> where it
>> was coated.  The "paper white"
>> It looks almost as if it spent some time soaking in a tray of coffee.
>> Camden Hardy
>> camden[at]hardyphotography[dot]net
>> http://www.hardyphotography.net