Archived posting to the Leica Users Group, 2002/02/17

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Subject: RE: [Leica] With XP-2, why develop B/W?
From: Herbert & Lee Kanner <kanner@acm.org>
Date: Sun, 17 Feb 2002 14:55:01 -0800

It's been a few years since I did black and white, but when I 
discovered XP, followed by XP2, I stopped using any other B&W film. 
What I did learn about it was to rate it at ISO 200 if I wanted the 
best results, and I found those results to be superb.  On the other 
hand, at ISO 400, the results were so-so, and at ISO 800 completely 
unacceptable.

Here is the explanation the I have read and concurred with.  In the 
thin places on the negative, the dye clumps do not overlap, giving 
the appearance of grain. With sufficient exposure, those thin spots 
will correspond to the darkest shadow areas, i.e., black on the 
print, where the "grain" will not be visible.  With general 
underexposure, the lighter (on the print) areas will suffer from this 
phenomenon.

Question: Why have I not noticed this effect with color negatives? 
Perhaps it is because the lack of overlap is hidden since there are 
three emulsion layers--a gap in one layer could be hidden by the 
existence of dye in one or more of the other layers.

Herb
- -- 
Herbert Kanner
kanner@acm.org
650-326-8204

Do not meddle in the affairs of cats,
for they are subtle and will pee
on your computer!
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