R:[APML] Pentax 67 N2 purge

[Gualdoni PierMario <piermario.gualdoni@novaceta.com>]

Joe,
is easy to have film curling with medium/high percentage of water in the
air (relative humidity from 50 to 70-80%), especially with medium
formats.
A simple but efficient expedient i've used to avoid the problem is to
encapsulate the camera with a plastic bag containing silica gel, sealed
with an elastic rubber band.

Regards
Piermario
================================================
Piermario Gualdoni
Milano
Italy
http://digilander.iol.it/bares

> ----------
> Da:   Joe Pedit[SMTP:jpedit@sph.unc.edu]
> Risposta a:   astro-photo@seds.org
> Inviato:      giovedì 30 settembre 1999 14.09
> A:    astro-photo@seds.org
> Oggetto:      Re: [APML] Pentax 67 N2 purge
> 
> Philip,
> 
> I recently started to use a Pentax 67 with my AP130 f/6.  I have
> noticed
> that on long exposures (45 to 50 minutes) using unhypered PPF that the
> lower left quadrant of the negative has stars smeared from the center
> to
> the corner.  Does this sound like film curl?  Short exposures (5
> minutes) do not show this problem.  My guide star is always near the
> center of the field and there is no hint of field rotation on the
> negative.
> 
> Joe
> 
> Philip Perkins wrote:
> > 
> > Has anyone fitted an N2 purge to a Pentax 67?
> > 
> > I am definitely seeing the need in the very damp climate here.  I
> would be
> > interested in doing this as non-invasively as possible.  The 4"
> field
> > flattener would form an effective gas seal, so it should work well.
> > 
> > I would be very interested in exchanging notes.  I have fitted an N2
> purge
> > to my Nikon F2 which was very successful.  There is a huge
> difference in
> > results.  I will write up some notes very soon.
> > 
> > Thanks
> > --Philip
> 
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