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

[etienne garbaux]

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