From: Judy Seigel (jseigel@panix.com)
Date: 04/10/02-11:33:07 PM Z
On Wed, 10 Apr 2002, Eric Neilsen wrote:
> Bob, I would suggest that it has more to do with how you heat rather than
> if you heat. The technique of using a hair drier has most certainly been a
> quick avenue of death for some printers. As with any tool, some just don't
> get it. Did you rehumidify the paper after you dried them? how hot was
> your paper? distance to paper? duration of heating? in other words, what
> is the quality of the heat of your heat source?
Probably few generalizations are possible... except how about the
following...
1. If you "cook" gum with heat, it's NOT going to be reversible.
2. If other media can be brought back to their original "nature" after
heat drying by letting them rehumidify, you have introduced MORE
variables, and the need for ever more precise timing.
Judy
> I have run the test for platinum in many of its forms and have not seen any
> loss of speed. Did you use platinum or palladium to run your test? Big
> difference between the two and how they react to loss or gain of RH in the
> paper. I have seen situations that require predrying, prehumidifing, post
> humidifying,... I would not come out and say in a blanket statement that
> heat drying does... it may and it may not.
>
> When I have an opportunity, I will try to heat dry cyanotype, kallitype,
> chrysotype and run the step test. But only after I replace the humidity
> lost during drying. It should also be noted that for chrysotype and
> platinum/palladium, that getting the paper dry might just be what is needed
> to achieve a certain color.
>
> Perhaps you'll notice that not all ferric oxalate will give you the same
> print out when dried. I am just referring to FO not AFO.
>
> It is the careful use of the heat that does indeed prevent the solution for
> soaking too far into the paper. This is a much unwanted effect in platinum,
> kallitype and I would suspect VDB.
>
>
> EJ Neilsen
>
>
> ----- Original Message -----
> From: "Robert W. Schramm" <schrammrus@hotmail.com>
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Wednesday, April 10, 2002 6:02 AM
> Subject: Heat drying
>
>
> >
> > Eric et al,
> >
> > Judy mentioned this effect to me some time ago. As she says, she has
> > tried it repeatedly for cyanotype and VDB. I did the same and added
> > platinum. I suggest you try it yourself using a 21 step wedge.
> >
> > I might suggest that the rapid drying you get with heat causes more of
> > the sensitizer to sit on the surface of the paper.
> >
> > As Judy says, a small fan works almost as well.
> >
> > Bob Schramm
> > Check out my web page at:
> >
> > http://www.SchrammStudio.com
> >
> > also look at:
> >
> > http://www.wlsc.wvnet.edu/www/pubrel/photo.html
> >
> > _________________________________________________________________
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>
>
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