[alt-photo] Re: Question for Platinum/Palladium printers

[Denny]

Etienne,

Thanks very much for that insight, the analogy is perfect.  

Denny

-----Original Message-----
From: alt-photo-process-list-bounces at lists.altphotolist.org
[mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On Behalf Of
etienne garbaux
Sent: Friday, December 30, 2011 10:20 PM
To: The alternative photographic processes mailing list
Subject: [alt-photo] Re: Question for Platinum/Palladium printers

Denny wrote:

>Thanks, I took a quick look but I think this test is really for soluble 
>iron, which I assume would wash out in normal processing. In the first 
>link, I think Photo Engineer has it right when he says  "These tests 
>will work for soluble Iron salts, but there is no good test for insoluble
iron salts.
>Fortunately for us, they are either inactive or show up as a visible 
>brown stain."

Not really so fortunately, from a process perspective -- the stain isn't
visible immediately after processing, it takes years/decades to develop as
the insoluble iron complexes slowly oxidize.  So it is only a guide to
residual iron contamination long after the fact.  The old tests for residual
iron attempt to accelerate this process.  If you read some of the scientific
papers describing the new test, it reportedly can be persuaded to indicate
the presence of insoluble iron -- but only by sacrificing the artifact being
tested.  Not really a problem for us, because we're checking a process and
can use test prints -- but a real problem for conservators.

All that said, Pt workers 130 years ago knew how to clear their images --
use several dilute hydrochloric acid clearing baths in succession.  Pretty
much all of the stained Pt and Pd prints I have seen were made in the last
30 years (most of these were hanging in galleries).  By contrast, I have
several hundred original Pt prints made from the late 1880s through the
1930s, not one of which shows any sign of residual iron or other processing
stains.  So, in my view, the best way to avoid trouble and be reasonably
confident that residual iron is not a problem is to just use the process
that we know works instead of trying to find a new way to do it.

Kind of reminds me of teaching reading in the US.  Since the ancient Greeks
(at least), children had been taught to read phonetically.  It worked.
Then, in the 1950s and '60s, educators felt a need to change things up and
started teaching reading by the "whole word" (or "see and say") method.
Children learned to read, but in general more slowly, and we turned a blind
eye while our educators raised 2+ generations of people who can't spell
worth a damn.  Then some bright entrepreneur started selling phonetic
reading courses, and the kids who used them had a huge advantage in school,
so every parent needed to buy them, and finally schools have begun to teach
reading phonetically again.  If it ain't broke, don't fix it.

Best regards,

etienne




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