From: clay (firstname.lastname@example.org)
Date: 01/29/02-07:53:54 PM Z
>Clay: What causes the "dreaded black spots"? Could it be the residue of
>the metals in the potassium oxalate?
I think (personal unscientific theory) there may be impurities or internal
sizing irregularities in the paper that sometimes serve as a 'focus' point
for accumulation of the metal. I've learned the hard way that the worst of
these can be seen immediately after coating if the paper is held up to a
(hopefully safe) light. They appear as darker areas in the coating. This is
hitting me particularly hard with Platine lately. The best strategy I have
found is to bring all your negatives that you think that you might someday,
maybe print, into the darkroom, and turn this sheet of Platine into a
perfectly fine test strip for all the negatives you've been meaning to
print. I have found no way of rescuing the paper if you have these blotches
appear after coating. I suppose if you can orient your negative so that the
blotch appears in the middle of a really busy area like a shrub, you might
get away with it.
Then of course, there are the beloved smaller speckies that appear only
after the print is dry. These can normally be etched away and spotted.
I filter my developer frequently, so I think the potassium oxalate is
probably not the culprit, especially since I don't get this with other
papers I am doing at the same time.
I also examine each piece of paper with a piercing gaze before coating to
look for possible rogue spots. If the paper has the, I just cut it up for
I may need to begin filtering my sensitizer and metal solutions with
Platine. I bought some lab grade filter paper and a funnel to give that a
If all this fails, I just switch papers. If you look at old posts on this
site, you will find the Platine speckle dilemma has been very much
discussed. It tells you something that a paper this unpredictable must be
capable of making some pretty outstanding prints if so many of us still put
up with its vagaries.
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