From: Tom Ferguson (tomf2468@pipeline.com)
Date: 04/11/02-08:29:03 AM Z
When I said "heat", I meant my "heat"!
When I "heat" something, it is with a hair drier and I suspect at least 110
degree F. I don't have a heat chamber (sounds great, but I would need a
bigger darkroom). Come to think of it, I do need a bigger darkroom!
So, yes, your points are valid. 80 degree F might be a good thing, 90
degrees might be. That I can't answer. But, for the typical user in the
typical darkroom, I would be concerned with "typical heat drying" (a hair
drier) for anything except platinum and suggest everyone do a quick test in
your own working methods/situations. Remember to allow time for the heated
paper to return to ambient humidity before printing.
Except gum, give up all "heat" hope with gum, just dry it at room temp (65
to 80 degree F seem reasonable).
In fact, someone mentioned "cooking" gum (damaging it) from the heat in
their exposure unit. My gums have been a lot more consistent since I added a
small fan to my UV bank. It doesn't take a lot of airflow to keep mine cool
:-)
-- Tom Ferguson http://www.ferguson-photo-design.com> From: Eric Neilsen <e.neilsen@worldnet.att.net> > Subject: Re: heat drying Re: Platinum respirator > > 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> > 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!
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