From: Mike Finley (mike@efikim.compulink.co.uk)
Date: 06/04/02-01:23:18 PM Z
This seems highly unlikely. If true, zone system development wouldn't work,
and I'm sure someone would have noticed.
-----Original Message-----
From: Joachim Oppenheimer [mailto:joachim@microdsi.net]
Sent: 04 June 2002 18:25
To: alt-photo-process-l@skyway.usask.ca
Subject: RE: long exposures, reciprocity failure and development times
As a sometimes-pinhole photographer I am aware that films differ in their
response to reciprocity failure at least at the lower part of the curve. It
is paradoxical that conventionally "Slower" TMAX-100 is "Faster" than
TMAX400, if one looks at Kodak's data sheets. Underdevelopment removes
silver halide uniformly from a piece of film so that a fixed percentage
removal, say 10%, will have little noticeable effect in an area of silver
halide deposition that is loaded with the silver salt but a proportionately
greater effect in the thinner areas - 10% of an arbitrary one picogram
silver halide leaves 0.9 picogram but 10% of 100 picograms still leaves 90.0
picograms. I think the guide directing you in the opposite direction is
incorrect. Joachim
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