From: Eric Neilsen (e.neilsen@worldnet.att.net)
Date: 04/11/02-12:43:40 AM Z
Tom, I think that your comments point out an important aspect to heat
drying. It is quite possible to over heat a coated piece of paper sensitized
with pt/pd salts. Might it also be possible to over heat other processes,
and the degree of over heating be controlled by proper control. i.e. some
processes require very little or no added heat from an external source other
than ambient room. There may be a small threshold in processes for heat
drying. Would one consider a paper to be dried with heat if the air source
was 80F in a 65F room? Does the Dmax suffer if the room temp is 80F during
the whole process and dried with only a fan?
Proper technique for the proper time and process : )
EJ Neilsen
----- Original Message -----
From: "Tom Ferguson" <tomf2468@pipeline.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Wednesday, April 10, 2002 7:12 AM
Subject: Re: heat drying Re: Platinum respirator
> I will agree that heat dried platinum, allowed time to return to normal
> humidity (or put in a chamber), is fine. I also have tested and am
> convinced. Even with time to humidify my cyanotype was "damaged" by the
heat
> (flatter and less d-max), gum was virtually destroyed!
> --
> Tom Ferguson
> http://www.ferguson-photo-design.com
>
> > From: Eric Neilsen <e.neilsen@worldnet.att.net>
> > Subject: Re: heat drying Re: Platinum respirator
> >
> > Yes Carl : ) , this was my point. and might it also be true for other
> > processes? If a dried paper is humidified after the drying process does
it
> > show the loss of density?<BIG SNIP>
> >
> >
> > ----- Original Message -----
> > From: "Carl Weese" <cweese@earthlink.net>
> > Subject: Re: heat drying Re: Platinum respirator
> >
> >
> >>
> >>> I haven't made the test in platinum, but I've made it in VDB and
> >>> cyanotype, and my students made it repeatedly. (They were required to
do
> >>> two "variables tests" per semester, and this was one of the easiest
!).
> >>
> >> I have done the testing with Pt/Pd and several papers. Different
humidity
> >> levels make an enormous difference to the tone of platinum prints, but
> >> heat dried sheets print exactly the same as those dried without heat as
> >> long as they are allowed to come back to the same moisture content.
<SNIP>
>
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