Re: [APML] Reciprocity of older films

[Brian larmay <power_windows4789@yahoo.com>]

Thank you renzo and Don..

Ill just have to point shoot and see how things go
next ne moon if its clear.

BTW, i have about 30 rolls of Super G 800 also..this
dated back to earliest 2/"99".

Is this a good aurora film?
I hardly think Ill use all that for aurora being that
solar minimum is almost upon us, but how about
meteors?
Perseids are coming and its looking like its going to
be a good show from what Ive read so far.

Clear skies and thanks for the info:)
Brian

> Brian,
> 
> I don't think you can compensate for exposure on
> nebulas and galaxies, shoot
> as long as you can without getting sky fog.  The
> main thing that happens to
> color film due to age is a change in color balance. 
> That is the reason for
> the expiration date on both consumer and pro films. 
> The color balance of
> consumer films is set to be best about mid way
> through the life of the film.
> Pro films start out near "perfect" color balance and
> must be stored cool to
> keep a reasonable (and tight or non changing) color
> balance until
> expiration.  Cool or Cold storage slows the color
> change.  There's a debate
> whether to freeze or not freeze for best results. 
> Kodak recommends both in
> different papers.  The other long term effect on
> film is the little spots
> that will show up due to cosmic ray hits.  The older
> the film, the more
> cosmic rays pass through.  Cosmic rays go right
> through refrigerators and
> freezers.
> 
> My film tests did not try to distinguish changes in
> reciprocity due to age
> on regular films.  I did see an increase in long
> exposure response for
> hypered PPF400 and PJ400 at 4 months and 22 months
> in a freezer.  Most of my
> film tests were done in the summer of 2002.  My
> testing of films like PPF400
> and PJ400 were on out of date film at that time, yet
> they performed very
> well.
> 
> The PPF400 needs hypering to perform best, and is
> much better 4 months after
> hypering.  Supra400 doesn't need any hypering.
> 
> Don
> 
> 
> > Hi all,
> > Does reciprocity of film change as it gets older?
> > The reason Im asking is I met up with an apml'r
> today
> > who gave me some ppf and supra 400 which was well
> > taken care of.
> >
> > Im not sure the date on the film but i think its
> like
> > "99" or "98".
> >
> > Do I have to compensate for exposure considering
> its
> > age?
> >
> > Thanks,
> > Brian
> >
> > =====
> > Homepage: www.astrobri.com
> >
> > Location:
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> >
> > Cat: I'm so handsome, there's a six-month waiting
> list for birds to
> suddenly appear whenever I am near!
> >
> >
> >
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=====
Homepage: www.astrobri.com

Location: 
Niagara Falls USA
geographic Longitude = 79W
Geographic Latitude = 43N
Corrected Magnetic Latitude = 53N

Cat: I'm so handsome, there's a six-month waiting list for birds to suddenly appear whenever I am near!


		
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