[LargeFormat] flattening of dry prints

[Richard Knoppow]

----- Original Message -----
From: "hairy possum" <pleohmy@yahoo.com>
To: <LargeFormat@f32.net>
Sent: Thursday, January 09, 2003 8:49 AM
Subject: [LargeFormat] flattening of dry prints


> Hi everyone,
>
> I printed several negatives the other night, it was
> kinda late when I finished, so I let them air dry.  Of
> course they curled and rippled as usual.  I am wanting
> to dry mount those prints tonight, and am wondering.
>
> IF I try to dry mount them without rewetting and
> drying flat, will the emulsion crack??  Would it be
> better to just wet them again, and dry in the dryer
> flat instead??
>
> I know I should have dried them flat the first time
> (:>)  but sleepy eyes and a long day convinced me not
> to do that.
>
> I promise to do better next time (:>)
>
> Any experience/knowledge on this will be appreciated.
>
> Thanks in advance,
>
> Lauvone
>
> =====
> www.Lauvone.com
>
  Air dried prints should not crack. Cracking is a problem
with heat dried prints where too much heat has been applied.
  The best method of flattening prints is to use a dry
mounting press, in fact, the drying method is outlined in a
handbook once published by Seal but no longer available.
  The press should be set for whatever temperature is going
to be used for mounting. It does not have to be high if its
being used only for flattening, 190F will do.
  For this process you need:
A dry mounting press
A flat weight the size of the print or larger. Ideally, this
should be a sheet of aluminum but plywood works OK.
Some release tissue.
Some clean heavy "Kraft" paper larger than the prints.
You may also want to use some padding in the press as when
dry mounting.
  The procedure is to first warm up the press.
Then dry out the Kraft paper sheets by putting them in the
press for about two minutes. Close but do not lock down the
press.
  After drying out the kraft paper place the print on a
sheet of it and cover the emulsion side with release tissue.
Place a second sheet of Kraft paper over the release tissue.
  Put the sandwich in the press. Close, but do not lock down
the press and allow to dry for about two minutes. You may
lock down the press after about 30 second if you like.
  Take out the sandwich and place under the flat weight
until cool.
  The print will be flat and will stay flat.
  Somewhere I posted the entire dry mounting pocess from the
Seal handbook. I thought I saved it but will have to look at
some old zip discs. If I can't find it I will type it out
again since it seems to be useful. Seal's procedure is
rather different from Kodak's and seems to work very well.
  As far as edge frilling; this seems to be a problem with
some papers and not others. For example, I've always had
frilling problems with Agfa papers and remember than Ansco
papers had the same problem (and also smelled the same).
Kodak papers seem to be free of it.
  Curling comes from the differential shrinking of the
gelatin layers and the support. Re-wetting the gelatin can
help but usually only temporarily. I suggest using a garden
"mister" to spray the surfaces. I don't think this will fix
frilling.
  When I print on paper I know frills I leave a large safe
edge or border so I can trim off the edge.
  I don't know where you are but in areas like Los Angeles
where very low humidities are often encountered (it was down
to 9% a couple of days ago) print and negative curling can
be a real problem. Usually, the prints and negatives
straighten out by themselves once the RH goes back up.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com