U of S | Mailing List Archive | alt-photo-process-l | Re: pt/pd mounting

Re: pt/pd mounting



On Sep 11, 2006, at 8:11 AM, Camden Hardy wrote:

Thanks to Liam and Gawain for the responses.

So that leaves us with one "busted" and one "doesn't really matter".

Anyone want to tip the scales?
Camden, I don't have any information to tip the scales one way or the other, but from where I'm looking, the scales are already tipped.

Your question was

Someone once told me (can't remember who or where or when) that since
pt/pd is an acidic process that mounting a print in pH neutral or acid
free mat board will actually shorten the life of the print.
This is a different question, as I read it, than whether using a buffered board, where the pH of the board has been raised to 8 or 9 with the addition of calcium carbonate, will shorten the life of the print. Both of the answers addressed this second question, and it makes sense that they answered this question, because that's probably what your vaguely remembered warning was referring to anyway.

The way I read it, both Liam and Gawain answered this seond question in the negative: using a buffered board shouldn't hurt your pt print, Lord willing and the creek don't rise. But the answer to your original question is also "no," and not just because as Liam says, a pt print isn't acidic when it's properly washed--even if it was, you wouldn't want to use an acid board. So you're left with the choice of whether to use a pH neutral board (100% cotton rag) or whether you want the additional protection of buffering against the formation of acid in the print over time.
Katharine





Camden Hardy

camden[at]hardyphotography[dot]net
http://www.hardyphotography.net


On Sat, September 9, 2006 8:36 pm, Liam Lawless wrote:

Platinum prints should not be acidic if properly washed after processing.
But platinum is a catalyst and turns atmospheric sulphur dioxide into
sulphuric acid which causes yellowing and embrittlement of the paper the
print is on. Old platinum prints are often quite acidic, so I see only
benefits from buffered boards.


Liam

-----Original Message-----
From: Camden Hardy [mailto:camden@hardyphotography.net]
Sent: 09 September 2006 18:19
To: alt-photo-process-l@usask.ca
Subject: pt/pd mounting


I've heard a myth I'm looking to bust or confirm, and I figured this would
be a good place to find out.

Someone once told me (can't remember who or where or when) that since
pt/pd is an acidic process that mounting a print in pH neutral or acid
free mat board will actually shorten the life of the print.

So my question is, within the context of pt/pd, how important is the pH
level of mat board for archival mounting?

Thanks,
Camden Hardy

camden[at]hardyphotography[dot]net
http://www.hardyphotography.net