FW: An exchange with Mike Ware (on Argyrotype)

Well I can't say much about that since I don't know how people was
processing their Kallitypes and Vandykes back then (Were they clearing
in citric acid? What was the concentration of their fixer? Did they
washed the prints enough?). My opinion is that if one process Kallitypes
and Vandykes so that no thiosulfate (except for a minute trace maybe -
which may actually provide protection from oxidation) and iron is left
in the paper, there isn't a reason to think that the stability /
longevity will be inferior compared to Argyrotype.

Removing thiosulfate is relatively easy: a good non-aggressive wash
after a 2 minutes 2% sodium sulfite hypo clearing bath (this is my
standard practice too along with citric acid clearing). Removing iron
also should not a problem with modern chelating agents (as you mention
in your "Platino-Palladiotype Process" article
http://www.mikeware.demon.co.uk/platin.html - others, see entry #4 in
the section "Improved Method for Platinum-Palladium Printing") or
good-old citric acid (which I always do).

Maybe you can describe me a method for testing that so that we can all
know if iron is left in paper even after clearing with EDTA and/or
citric acid. Testing for thiosulfate also is possible and easy. I can
make both of these tests on some of my Vandykes.

If I can't find either thiosulfate or iron in the paper, can we draw the
conclusion that if properly processed (leaving no residual thiosulfate
and iron in paper), Vandykes (or Kallitypes) should be as stable as
Argryrotypes?

Best regards,
Loris.

-----Original Message-----
From: Mike Ware [mailto:mike@mikeware.co.uk]
Sent: 22 Mart 2006 Çarşamba 12:46
To: Loris Medici
Subject: Re: An exchange with Mike Ware (on Argyrotype)

...

I would like to turn our discussion towards a question of objective
historical evidence that I find interesting:
in the photograph collections of the UK, and elsewhere, I have seen many
salt prints and cyanotypes from the 1840s, and many platinum prints from
the 1890s on. Yet I do not think I could show you a single Van Dyke or
Kallitype from 1900-1910, when these processes were supposed to be most
popular. Have I just missed them? Have you heard of any? If not, what is
the explanation for their absence? (I have heard the explanation that
there are many van dykes and kallitypes "out there" pretending to be
platinotypes - but have you ever seen a shred of evidence for this
assertion?)

If it interests you, I would be quite happy if you raised the questions
in this last paragraph publicly.

...
Received on Thu Mar 23 02:38:01 2006