RE: [APML] Adapting Nikon F3/T for gas purge

["R. Scott Ireland" <ireland@gate.net>]

Hello Michael:

>      I do not hyper my Kodak PPF film and get excellent results.
> My exposure
> times are 35 minutes at f/5.6,  45 minutes at f/6 and 55 minutes at f/7.
> Actually, the unhypered PPF has slightly more red sensitivity and
> contrast than
> the hypered PPF.

No question that you're achieving excellent results with unhypered film.
Are you suggesting, though, that unhypered PJ400 should perform as well or
better than the hypered emulsion?  Although I've not yet had enough personal
experience with the emulsion, researching the archives here seems to
indicate most people prefer to hyper this film.

Is PPF the same/similar emulsion as PJ400?  Would the hypering
characteristics of each film be the same/similar?

>  The only advantage I see in hypering PPF is for
> blue objects
> like galaxies

Why would that be?  Does hypering PPF make it more blue-sensitive somehow?

> Unfortunately, moisture
> in the atmosphere above the ground and low elevation can also
> result in poor
> results.

Fortunately, moisture and lack of elevation notwithstanding, South Florida
is blessed with usually excellent seeing, and the winter months produce some
excellent transparency as well.  Last new moon, in quite mediocre and
somewhat light-polluted conditions, I recorded stars to 12.5 magnitude with
a 55mm f/2.8 lens at f/4, and the nebulas were all there in force also!

Thanks, Michael, for all of the advice and help.

Scott


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