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

[Denny]

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."  

-----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 4:42 PM
To: The alternative photographic processes mailing list
Subject: [alt-photo] Re: Question for Platinum/Palladium printers

Denny wrote:

>I'm using 3% citric acid for 5 minutes followed by HCA with Stonehenge 
>and it seems to be working.  I mask the negs for white borders and the 
>borders look clear.  Is there a more definitive test for residual iron 
>that should be used?

Definitely, if you want some assurance that your prints are archival
-- visible clearing tells you nothing about that.  There are a number of old
tests that work, but a modern method used by conservators is discussed here:

http://www.apug.org/forums/forum42/89406-residual-iron-test.html

http://www.irongallink.org/images/file/pdf%201%20_iron_ii_test__ok.pdf

http://www.irongallink.org/images/file/pdf%202_preparation%20of%20ascorbic%2
0acid_ok.pdf

http://www.irongallink.org/images/file/pdf%203_fe%20test%20artikel.pdf

http://www.irongallink.org/images/file/icom14_161.pdf


Also, Dequest (http://www.dequest.com/) reportedly makes some iron
sequestering agents that are strong enough to solubilize insoluble iron
complexes.  Some of these may be suitable for clearing iron-based prints,
assuming that they have no deleterious side effects, but I am not aware of
any testing having been done for this application.

Best regards,

etienne




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