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From: howard@sfmag.UUCP (H.M.Moskovitz)
Newsgroups: net.rec.photo
Subject: Re: Pushing high-speed film
Message-ID: <788@sfmag.UUCP>
Date: Mon, 2-Dec-85 11:30:30 EST
Article-I.D.: sfmag.788
Posted: Mon Dec  2 11:30:30 1985
Date-Received: Tue, 3-Dec-85 20:08:39 EST
References: <259@watmath.UUCP>
Distribution: na
Organization: AT&T Information Systems, Summit, NJ
Lines: 40

> 
> Recently, there was an article in this news listing talking about high speed
> films, and pushing them to high ASA's (i.e. 3600+).
> 
> I was wondering how can you do this without your film coming out super-grainy
> or not at all. (Do you have to inform your processor or what?)
> 		
> 				Rick...

Pushing film speed depends on the type of film you're shooting.
In black&white, grain and sharpness can be controlled by your
developer. Tri-x or HP-5 can be shot at 800 asa with very little loss
in sharpness. These films can be shot equally at 1600 or 3200
if developed in Acufine or Diafine developers. With Diafine, a
two step developer, HP-5 at 1600 is a little sharper than at 400
with D-76. It is remarkably sharp at 3200 as well.

Color slide film can usually take a one-stop push with only a small
loss in sharpness and color saturation. A two stop push suffers
a little more. This is due to there being only one chemistry
available and the push is an over-development compensation to 
under-exposure. However Kodak and Fuji have released chrome films
that have an standard index of 800 and 1600, respectively and
can be pushed easily to 1600 and 3200. The grain is abpout the same
as Ektachrome 400 shot at 800 (which is very good).

Color print film does not handle push processing well and many labs
will not even offer it. However Kodak has the vr-1000 film (1000 asa),
and Fuji has their HR-1600 print film which is very nice.

So the conclusion to this is: for black and white choose a developer
to suit your needs, for color choose the film that does.

-- 


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					Howard Moskovitz
					AT&T Info. Systems
					attunix!howard