From: Bob Kiss (bobkiss@caribsurf.com)
Date: 08/14/03-02:16:41 PM Z
DEAR RAY,
I found that my black spots were due to my Ferric Oxalate precipitating
around the screw threads on the top of my brown glass bottle where the
dropper cap screws on leaving this deposit of powder. The powder falls into
the bottle where the eye dropper sucks it up and deposits it in my
sensitizing mixture in my shot glass. No spots are visible at coating time
but show up only after the long and arduous task of exposing and processing.
I carefully pour my FO into a clean beaker, wash the bottle and
especially the screw threads with distilled water. I filter the FO and pour
it back into the brown bottle and, PRESTO CHANGE-O no more black dots. You
can have similar problems with the Pt and Pd solutions and the experts all
recommend regular filtration.
Re: Etching, it scares me but Dick Arentz and many others have
suggestions in their books. I am sure that the more experienced PT/PD
printers on this list can take it from here.
CHEERS!
BOB
----- Original Message -----
From: "Ray Bidegain" <ray@rbstudio.com>
To: <alt-photo-process-l@usask.ca>
Sent: Thursday, August 14, 2003 4:47 PM
Subject: Black Spots
> Hello:
>
> I am a platinum palladium printer and suddenly I am getting a large number
> of prints with black spots. I have not really changed anything about my
> process that I can think of and am wondering if there is a packing order
of
> likely culprits. How should I attempt to find the problem. Lastly any
> advise on etching them off the prints I have?
>
> Thanks for your help.
>
> Ray Bidegain
>
This archive was generated by hypermail 2.1.5 : 09/05/03-09:30:46 AM Z CST