Re: Clearprint Vellum

Hi Stephen,

I'm familiar with the terrible "black spot syndrome", and fortunately have
not experienced it with any papers or chemistry I've used for PT/PD.

What I was referring to is tiny pepper like black spots that are inherent in
the Clearprint Vellum itself before you even apply anything to the paper....
it comes that way and the little spots are still there when you finish your
print. So, it really has nothing to do with the PT/PD process. I was asking
about this because I wondered if this was just true of the roll of Clearprint I
happened to get, or was this true of all Clearprint Vellum. I was hoping
that folks who had purchased it would take a quick look at their paper with a
loupe and see if the roll or sheet that they have exhibits this "feature".

Mark Nelson

In a message dated 2/22/04 9:44:01 AM, sh@stephenharrison.com writes:

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> I have had problems with black pits for years and years in platinum. It is
> always a problem and I suspect is has to do with metallic filings and
> contaminates in the paper fibers.
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> I use foam brushes with no metal ferrules.
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> I filter all of my chemistry with a suction filter to eliminate extrinsic
> sources of metal especially in the ferric oxalate
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> Some of the newer papers designed for platinum have less metallic
> contaminates than the clearpoint papers.
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> My guess it that the translucent papers not designed  for platinum  are more
> contaminated with metallic filings than those papers that are designed more
> for platinum.
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> The pits cannot be retouched especially if they occur as a black pit in a
> white sky where they seem to gravitate to drive the printer nuts
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> Stephen Harrison
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Received on Sun Feb 22 11:05:12 2004