Re: [APML] tech pan revisited

["DEREK BAKER" <derekb@sympatico.ca>]

Perhaps an interaction between the backing material/substrate and the
emulsion, or water/condensation/oil from fingers on back of film touching
the emulsion as it is rolled?

Just guessing but thought I'd share my suggestions...
----- Original Message -----
From: Scott Hammonds <shammonds@creatorsview.com>
To: 'Discussion of Film Astrophotography' <astro-photo@seds.org>
Sent: Friday, September 05, 2003 3:02 PM
Subject: RE: [APML] tech pan revisited


> Derek,
> It only happens to the film after exposure that is taken up in the
> camera spool. If I don't wind the camera after the last exposure I get 2
> frames without the lines.
>
> Scott Hammonds
>
>
> -----Original Message-----
> From: astro-photo-bounces@seds.org [mailto:astro-photo-bounces@seds.org]
> On Behalf Of DEREK BAKER
> Sent: Friday, September 05, 2003 5:57 AM
> To: Discussion of Film Astrophotography
> Subject: Re: [APML] tech pan revisited
>
> For what it's worth...Could it be a) a linear light leak parallel to the
> axis in the hypering film drum, or b) the film was intermittently
> rubbing/touching something in the drum as it was rotated
> before/during/after
> hypering? or c) something similar to a) or b) during development? IMHO,
> In
> the case of b) or c) chemicals may have been unevenly distributed (too
> much
> then too little) in lines parallel to the axis of rotation/perpendicular
> to
> the sprockets?
>
> Good luck
>
> Derek
>
>
> ----- Original Message -----
> From: Jerry Lodriguss <jerry@astropix.com>
> To: Discussion of Film Astrophotography <astro-photo@seds.org>
> Sent: Friday, September 05, 2003 1:31 AM
> Subject: Re: [APML] tech pan revisited
>
>
> >
> > >  Scott's somewhat puzzling image is here:
> > >http://www.creatorsview.com/pages/demo.html
> >
> >
> > Hi John,
> >
> > Thanks for the link.
> >
> > I was wrong about having seen lines like this before from scratches
> from
> > dirt in the felt light trap.
> >
> > The lines appear to be dark lines of density in the negative image.
> They
> > are not scratches where the emulsion was removed which would make dark
> > lines in the positive image.
> >
> > This implies a light source.
> >
> > They are pretty straight but don't always run parallel.  They are not
> > static electricity, which would look like lightning.
> >
> > It certainly doesn't look like the emulsion cracking.
> >
> > It doesn't look like any kind of moisture during exposure, or
> development
> > problem.
> >
> > The predominant lines are light in the positive image, but there are
> also
> > dark lines on each side of a light one. The dark lines seem more
> diffuse.
> >
> > In one case (4th line from the left), a single light line at the
> bottom
> > forks into two lines at the middle of the frame. The 5th line from the
> > right does the opposite.
> >
> > This is just a crazy mystery!
> >
> > Jerry
> >
> >
> >
> >
> >
> >
> >
> > Photoshop for Astrophotographers - http://www.astropix.com/PFA/PFA.HTM
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > _______________________________________________
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> > Astro-Photo@seds.org
> > http://seds.org/mailman/listinfo/astro-photo
> >
>
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