[pure-silver] Re: DELTA 100 AS REPLACEMENT FOR Tmax 100
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Wed, 9 May 2007 12:18:27 -0700
----- Original Message -----
From: "mail1" <mail1@xxxxxxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Wednesday, May 09, 2007 9:11 AM
Subject: [pure-silver] Re: DELTA 100 AS REPLACEMENT FOR Tmax
100
Richard wrote
"If it works the effect is to lower the contrast of the
highlights.
Actually, the stain _is_ linear in that it is exactly
proportional to the
silver density, however, its effect on the paper depends on
the stain
density so its effect is greater for highlight than for
shadow areas."
.....its effect on the paper depends on the stain density so
its effect is
greater for highlight than for shadow areas.....
Yes its effect is linear on the film, but is its effect on
the paper linear?
Jonathan Ayers [mail1@xxxxxxxxxxxxxxxxx]
I think I agree with this. The stain is a linear
function of the silver density on the negative but its
effect on variable contrast paper is to create a curve on
the negative characteristic resulting in contrst which
becomes less with negative density. That is non-linear.
At some time in the distant past someone did some
sensitometric testing and posted the results to the web.
I've long since retired the computer this was stored on but
it did show the effect.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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