RE: Black spots in Pt./Pd.

How about contamination in the foam brush rather than an abrasion issue?
Where did your foam brushes come from? I also find that a 2" foam brush is
more likely to give a better coating than a 1 " even when coating down to
5x7 or 4x5.

Eric Neilsen Photography
4101 Commerce Street, Suite 9
Dallas, TX 75226
214-827-8301
http://ericneilsenphotography.com

> -----Original Message-----
> From: Sandy King [mailto:sanking@clemson.edu]
> Sent: Tuesday, August 09, 2005 12:17 PM
> To: alt-photo-process-l@sask.usask.ca
> Subject: RE: Black spots in Pt./Pd.
>
> Bob,
>
> Thanks for the informative reply.
>
> I have now figured out that the problem was indeed the Lenox paper,
> but it was not caused by the paper itself, or by the chemistry, but
> by the way i coated the paper. The thing is, I was doing some 4X5
> tests and the small 1" Richeson that I normally use for this is not
> to be found, so I used instead a small 1" foam brush. Well, the
> surface of the Lexox paper abrades *very* easily and it turns out
> that the abrasion is the cause of the spots. The other papers that I
> use have a harder surface and the foam brush did not cause the same
> problem.
>
> Have another small Richeon on the way so will wait to do any more
> tests on Lenox until it arrives.
>
> Sandy
>
>
>
>
>
> >DEAR SANDY,
> > My 3 cents...
> > I have never found any problem with Lennox so I feel that is a low
> >probability. What I DID find is that I have to clean the necks of my
> Ferric
> >Oxalate dropper bottles and the inside of the dropper cap EVERY TIME
> before
> >use. The crust of desiccated FO on them can fall into the solution as
> fine
> >clumps or crystals and create black spots upon development. I had black
> >spots on my prints using Lennox, Cranes Platinotype, and COT before I
> >started doing this and I have never had any spots since!
> > If you don't use droppers look for some place where the FO can dry
> and
> >crystallize as the source of trouble.
> > Some suggest that, if your metal solutions aren't warm enough
> >you can get
> >precipitates that can cause similar problems but, living in the tropics,
> I
> >don't have that problem Some suggest that roller paper trimmers emit
> shards
> >of iron or steel that can cause the same spots but I use a roller trimmer
> >and have never had a problem with any of the papers above.
> >
> > Please check my website: http://www.bobkiss.com/
> >
> >-----Original Message-----
> >From: Sandy King [mailto:sanking@clemson.edu]
> >Sent: Tuesday, August 09, 2005 11:57 AM
> >To: alt-photo-process-l@sask.usask.ca
> >Subject: Black spots in Pt./Pd.
> >
> >
> >Another Pt./Pd.question.
> >
> >I have not done any Pt./Pd.printing in about 6-8 months and when I
> >began trying to calibrate my materials again I ran into a problem
> >that I have not seen before, small black spots on the print that
> >appear during development.
> >
> >The chemistry that I am using 1 part of 25% ferric oxalate plus 1
> >part of 20% palladium chloride. The solutions are clear and are
> >giving very good Dmax, even though they were mixed several months ago.
> >
> >The paper is Lenox, which I have not previously used for Pt./Pd. printing
> >
> >Does this sound like a paper issue, chemistry issue, or some type of
> >contamination I am not understanding.
> >
> >Sandy
Received on Tue Aug 9 12:48:49 2005