Re: [APML] 400F (was: Alternative Anti-Vignetting Photoshop Technique)

[Matt BenDaniel <matt@starmatt.com>]

Herm,

My understanding of pushing is that it doesn't change the ISO recording
power of the film.  It just stretches what did record.  I think if there
is some faint feature beneath the toe of the film response curve, it
won't be revealed by pushing.  Supra 800 film will record faster than
P1600 (even though it is ostensibly ISO 1600), because P1600 is
essentially a 400 speed film designed for pushing.

I think your E200 M33 shot is underexposed at 30 minutes, if what you
intended was to record the faint outer arms.  Exposing longer will burn
out the core, and as I mentioned, I'd shoot a second shorter shot and
mask that in.

Also, pushing almost always makes the grain worse, even on a film like
E200 that was designed for pushing.  Grain is the principal noise we
wish to minimize in film AP.  The reason I push is as a latter resort
when something happens in the field (e.g. I make a mistake) and the film
is underexposed.

Matt

Herm wrote:
> 
> Sean, I agree it does make the slide thinner, and I agree it does reduce the
> dynamic range, but how does that reduce the sensitivity of the slide film to
> faint light?.. the hypered pj400 literally captured more of the neutral colored
> portions of the galaxy..
> 
> Note how even pushed +3, E200 still has less grain than PJ400?
> 
> Sean Walker <vze2c3z8@mail.verizon.net>  wrote:
> 
> >Herm, pushing E-200 3x just makes the slide thinner, and you lose alot of
> >dynamic range that way, so it's not really a good comparison.
> >
> >Sean Walker
> >
> >> From: Herm <hermperez@worldnet.att.net>
> >> I have a comparison on my web site between these two films on M33,
> >> please check it out: http://home.att.net/~hermperez/e200_vs_pj400.htm
> >>
> 
> Herm
> Astropics http://home.att.net/~hermperez
> 
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-- 
Matt BenDaniel
http://starmatt.com

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