Archived posting to the Leica Users Group, 1996/05/20

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To: leica-users@mejac.palo-alto.ca.us
Subject: Re: Long Exposures...
From: Eric Welch <ewelch@gp.magick.net>
Date: Mon, 20 May 1996 16:58:48 -0700

At 06:07 PM 5/20/96 -0400, you wrote:

>	How does he compensate for reciprocity failure?

If I remember correctly, T-Max films are very good at not suffering a lot of
reciprocity failure. But there is some. It's easy. You just test like you
normally would with the Zone system, and then use a densitometer to find out
when density right. With sheet film and roll film, it's not that hard.
Because seven minutes only 8 stops from about 5 second expsoure, or about
one roll for each test of 120 film, or less than a 10 sheet box. Not that
much film to waste to get the numbers one want. If you start with the Kodak
chart for your film, probably only three or four rolls of film need be used
for a full test, if one is careful.

==========================
Eric Welch
Grants Pass Daily Courier


Replies: Reply from Wolfgang Sachse <sachse@msc.cornell.edu> (Re: Long Exposures...)