[pure-silver] Re: Phototec times for Tri-x and Tmax 100
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Tue, 26 Aug 2008 07:25:12 -0700
----- Original Message -----
From: "ERoustom" <eroustom@xxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Tuesday, August 26, 2008 6:51 AM
Subject: [pure-silver] Re: Phototec times for Tri-x and Tmax
100
Hi Janet,
There's no need to develop 120 film any longer than 135
film is
there? A 36 exp. roll of 135 film has about the same
surface area as
a 12 exp. roll of 120. They get same the treatment - or
have I
misunderstood something along the way?
The developing time is affected by the overcoating of
the emulsion. Overcoating is a thin layer of gelatin
intended to protect the emulsion from abrasion and other
damage. The developer must penetrate the overcoat to reach
the emulsion. This can change the "induction time", that is,
the time it takes after the film in placed in the developer
for the image to begin to appear. This time is also affected
by temperature in a nonlinear way. That is one reason that
developing times vary with temperature at a different rate
than is predicted by simple chemical laws.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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