Re: [APML] Question re efficient use of film vs Quality

["Andrew Schott" <aschott@cfl.rr.com>]

Film itself is fairly stable and can be stored in a camera for a long time.  Latent images, on the other hand, are not stable and will tend to degrade visibly after a very short time.  Depending on the film, the type of image, and the conditions of it's storage, the latent image can begin to degrade in as little as a day.  Usually, the first to suffer is the contrast or dynamic range followed by color shift, resolution and grainyness.

I've tried it with black and white TRI-X before.  My group used to use 36 exposure rolls of hand loaded TRI-X (from 100' bulk) for nightime meteor surveillance.  I'd usually develop our efforts at the end of the week or during the first clouded out night, which ever came first.  We'd push the film until the fog got so great you couldn't find the stars (sound familiar?)  You could consistently see a *quality* difference in the images with longer latency.  I began to notice differences between images recorded on different nights on the same roll.  We were trying to determine the effects of seeing and some of the film results weren't matching up to what we were observing.  It was after a two week weather related layoff that we noticed the biggest problems with sky fog and loss of faint data.  Images on the rolls that had been sitting for that time, in camera, had really faded out while the fresher images looked much cleaner.  Some of it could be the seeing.  When you're pushing!
 film as much as we were back then, minor differences between nights did make major differences in fog limit and resolution.  But we never saw a case where a stored roll was better than a freshly took one.

We didn't actually test it but reciprocity seems to suffer in long latency.  Our photos were basically black or white, not a lot of information in the grayscale in meteor photos.  Planetary work would probably suffer more from latency than our stuff did due to increased reciprocity failure.

Just watch the pros in the movie industry.  Ever see a film company shoot part of a movie then stop production?  Do you think they leave their film in the camera or store it undeveloped on the shelf?  Anything shot is usually developed within hours of production.

For me, the two biggest advantages to the digital realm is the short roll, (in other words, I can go out and take one picture and see what it looks like and not have to burn a whole roll of film to do so) and the insensitivity to heat (digital cameras don't care if you leave them in the hot car all afternoon).  Of course, latency will never be a problem in the digital world unless memory chips become time sensitive:-)

Now that should get some discussion started!

Andrew Schott


----- Original Message ----- 
From: "Stuart Heggie" <stuart.j.heggie@sympatico.ca>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Sunday, June 22, 2003 10:04 AM
Subject: [APML] Question re efficient use of film vs Quality


> Okay - this one has been nagging for a while - I have been diligently 
> using the entire roll of film before processing (especially given the 
> end of Supra 400). I sometimes take months to get through a roll and 
> most of the folks on this list are publishing shots they took in the 
> past few days. Am I losing quality delaying processing? I just hate to 
> waste film (Scottish upbringing being part of the problem).
> 
> I have two nights of hopefully great pics on a fresh roll -should I 
> process it or wait for another week or two in case the new moon presents 
> further opps? Or just finish the roll whenever as it doesn't hurt to 
> keep it in the camera.
> 
> Help?
> 
> Stuart
> 
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