Re: [APML] Black Negs a new developement

["John C. Mirtle" <jmirtle@shaw.ca>]

Brian;
    Quite the mystery! There are really only 3 things that can darken the film -
hypering, humidity and light. I stopped buying Lumicon film about 10 years ago
because they couldn't supply consistently hypered film. With a standard 7 minute
development some rolls came out with a nice light gray background, another roll
would come out almost black, right through the socket holes. If your successful
daytime shots came from the same roll as the hooped Ha shots, then that isn't
the problem.
    Tech pan sucks up moisture like a Babel fish sucks up brain wave energy,
darkening the film. However, this is usually uneven giving a 'mottled'
appearance. For what you are describing you would have to be standing under a
spritzer bottle during the exposure! That leaves light, possibly from inside the
camera, but at a low enough level that it doesn't get picked up with unhypered
film. Are there any batteries in your camera? I am wondering if you are having a
problem similar to the Olympus OM2. After the shutter is open for 2 minutes a
red splodge will start to grow from the center of the film, caused by the camera
itself. This will occur even if the electronics are turned off - the batteries
MUST be removed to prevent this problem. Any chance of something similar with
your camera?
    It would be interesting to cut off a control piece of film from the roll you
are about to use, just before you load the camera. This could at least confirm
or remove the film from the list of suspects. 30 to 60 minute shots at f4 with
Ha should show little background darkening. You should be able to go for at
least 4 hours under a good sky. I shoot for 45 minutes at f1.5.

John Mirtle
Calgary, Ab. Canada

----- Original Message -----
From: "Brian Sledz" <brianhome@email.msn.com>
To: <astro-photo@seds.org>
Sent: Monday, December 10, 2001 9:15 AM
Subject: Re: [APML] Black Negs a new developement


> Hello Again,
> I seem to have no luck developing Lumicon hypered tech pan.  I took 4 more
> TP shots Saturday night, none came out.  I have not had any astro shots come
> out.  Four tries now and all sessions black negs.  I am thinking I should
> only be going 4-6 mins in d19?  I went 8 minutes on Saturday night and all
> black negs again.
> I took daytime shots used the same developer for 8 minutes and the shots
> came out.
> At first I kept trying to blame something else, but it must be the hypering
> developing combo ain't a workin.  These exposures Saturday were Halpha
> filter, Pentax SDUF II @f4, 35mm TP 30-60 minutes.
> Any tips?
> thank very much
> Brian



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