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

[EJ Photo]

Well, the clearing of prints has indeed evolved over time. When I first
learned to print, it was HCL all the way; three baths, all mixed the same,
use it so that the last one was clear - no color. And yes, the first bath
would indeed get cloudy and colored so later in my practice I cleared with
distilled water rinse, then acid.  Citric Acid, Oxalic acid had their place,
but HCL was cheap and did the job. Along came the late 80, and early
nineties and I saw Ware's paper on pt/pd printing, and hear of additional
uses of EDTA, sodium sulfite. These are both in hypo clearing agent and did
seem to make some sense. 

Progressive baths from disodium to tetrasodium EDTA moves from acid to
basic. One need only feel the paper after a clearing in HCL compared to EDTA
and other acid to know that the paper structure was changed by the HCL; it
is now stiffer.  Having had many conversations and seeing prints at John
Stevenson's Gallery in Santa Fe, Platinum Plus many of us moved away from
straight HCL or acids to less aggressive clearing agents. Some of that old
time staining was part of the print, at least for those made in the early
period of printing and those selling them were not bothered by it. 

How clear is clear and at what cost to the paper? 
 
Tests on your process can be done with sample prints to avoid the blue stain
that comes with many of the residual test.    

Eric Neilsen
Eric Neilsen Photography
4101 Commerce Street, Suite 9
Dallas, TX 75226
 
www.ericneilsenphotography.com
skype me with ejprinter
Let's Talk Photography
 
-----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: Saturday, December 31, 2011 4:48 PM
To: The alternative photographic processes mailing list
Subject: [alt-photo] Re: Question for Platinum/Palladium printers

Loris wrote:

>I remember to read that HCl severes some of the H bonds in the 
>cellulose molecule, that's no good - especially in the context of 
>pt/pd printing, where the image is stronger than the support.

Again, all of the antique Pt prints that were cleared in HCl and to 
this day show no apparent degradation of the paper suggest that, at 
the very least, any macro damage from the practice can be held to 
imperceptible levels with careful processing.

Best regards,

etienne





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