[pure-silver] Re: High B+F with DS-10
- From: Ryuji Suzuki <rs@xxxxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx, jblack@xxxxxxxxx
- Date: Thu, 03 Feb 2005 19:41:23 -0500 (EST)
From: "John Black" <jblack@xxxxxxxxx>
Subject: [pure-silver] Re: High B+F with DS-10
Date: Thu, 3 Feb 2005 18:05:00 -0500
> For photographic purposes, my definition of fog is a bit broader than just
> the conversion of non-light exposed silver halide to metallic silver. I also
> include any general (not image specific) density in a negative. This
> definition also includes dye remnants and stains.
Can you call your measurement overall nonimage density or NID or
something other than fog?
> I once scrubbed the emulsion off of several 35mm films in order to measure
> the base density so I could determine the true emulsion fog density by
> difference. I was amazed at the presence of gray and lightly colored
> density I found in the plastic of the base. Tri-X had a gray base density
> of about 0.20 and a total fb+f of about 0.30 giving an emulsion fog level of
> 0.10.
You know what you scrubbed off contains some of the non-fog density
(like leftover dye, gelatin itself, stain from fixer you observed, and
whatnot) and the actual fog is less than 0.1 right? A good comparison
specimen is the same film wetted in non-developer solution and fixed
identically.
--
Ryuji Suzuki
"Keep a good head and always carry a light camera."
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