Re: [APML] Speeding up film with cold weather

[Alan Voetsch <critter12952@yahoo.com>]

Hi Jerry,

--- Jerry Lodriguss <jml@astropix.com> wrote:

> >My results so far show that Supra recorded well
> over
> >twice as much light in a 330 minute exposure as it
> did
> >in a 140 minute exposure. This film is a slow, but
> >steady collector of light.
> 
> 
> How did you measure twice as much light?

I don't have a way to measure it. The prints show it
and after looking at the negatives just now, they not
only show more nebulosity, but many more stars as
well.
 
> >That really surprised me, as I assumed 150-180
> minutes
> >would be my upper limit. I can occaisonally see 5.6
> >magnitude stars here, but I'm 50 years old. I'd
> guess
> >6.0+ would not be out of the question for younger
> >eyes.
> 
>  From the darkest site, 60 to 90 minutes at f/8
> would be about max, and 
> that's only 120 to 180 minutes minutes at f/11, and
> you are at f/10.

I can't explain it, I ain't a genious. :-) The facts
show that I can keep soaking up light for at least 5
1/2 hours.

 > Perhaps the T/stop of your scope is much slower
than
> the f/stop. Maybe you 
> are closer to T/16.

Would you have any idea how I could figure that out? 

> Of course, you can also go past the skyfog limit and
> keep building density 
> in the film, but loosing faint stuff also.

That doesn't appear to be the case.
 
> Five and a half hours and 400 ISO film with good
> reciprocity failure at 
> f/10 is just causing a mental disconnect on my part.

Sorry, but maybe it's the film. I've been using it for
3 years now. It starts out more slowly than other
films I compared it to (Fuji 800 and LE400). Way
slower. But it never slows down, You keep getting
these incremental increases in light gathering that
match the exposure time. I expected it to drop off
after a couple of hours, but it doesn't. 

Sorry I was slow responding, but it took me all day to
get around to going through my negative box.

Alan

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