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Re: [APML] Black Negs a new developement
what about contaminated developer?
a few traces of fixer in paperdeveloper can cause photographic
paper to fog. this can happen with film as well but only with
very slight traces of fixer.
Albert
Monte Wilson wrote:
> Its starting to sound like the developer/development may be the cause. I
> know you said you are using fresh stuff and like to make new batches.
>
> Are you using to much agitation, too high a temp, wrong concentration? If
> you have a local friend doing d-19 too, send some to them to do it. That way
> you can start to eliminate areas of potential trouble.
>
> I know these all sound a bit elementary but I'll be the first to admit that
> no matter how careful I am gremlins can get in.
>
> Monte
>
> ----- Original Message -----
> From: Robert Reeves <reeves10@swbell.net>
> To: <astro-photo@seds.org>
> Sent: Tuesday, December 11, 2001 4:17 PM
> Subject: Re: [APML] Black Negs a new developement
>
> > > thick enough to ruin the film. I am in the far west suburbs of Chicago,
> > on
> > > each night I am sure we were in the 60% humidity range. Is that too
> high
> > > without a purge?
> >
> > Thats high enough humidity to NEED a purge, but not so much that it will
> > turn the negative completely black. Before I fabricated the purge system
> > for my Schmidt camera, half hour Tech Pan exposures often hit higher
> > humidity than that. The film was open to the air inside the large volume
> of
> > the Schmidt camera. It badly reduced image contrast, to the point of
> > rendering the exposure useless, but didn't turn TP black. It was a very
> > dark gray but the image was still visible.
> >
> > Robert Reeves reeves10@swbell.net
> > 520 Rittiman Rd. www.robertreeves.com
> > San Antonio, Texas 78209 210-828-9036
> > USA 29.484 98.440 200 meters
> >
> >
> > -- APML Archives at <http://astro.umsystem.edu/apml/> ---
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> >
>
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