------- Forwarded Message Follows -------
From: Self <CCP/KEITH>
To: TERRY KING <101522.2625@compuserve.com>
Subject: Re: Curves in Internegs
Reply-to: keith@ccp.arizona.edu
Date: Thu, 22 Feb 1996 17:16:38
On 19 Feb 96 TERRY KING <alt-photo-process@vast.unsw.edu.au> wrote:
> In which branch of alt would a reversed S curve be best used.
>
> Is there anyone who could run a worksho to demonstrate which curves are best
> used for what with illustrations and even how-to demonstrations. I, for one,
> would be in the front row.
>
> Or has digital imaging reached the stage where we do not need to worry any more
> about how to do it with film and developer ?
In the US, the high priest of sensitometry would have to be Phil
Davis. He gives workshops twice a year in Bisbee, Arizona (just a
stones throw from Mexico) as well as other locations such as the
University of Michigan. I have participated in this 5 day workshop
and recommend it highly.
Phil has also formulated a developer called DI-13 for use in
situations of extreme subject contrast that displays the very sort of
reverse S-curve mentioned by Klaus. With Kodak TMX and Agfa APX it
produces a relatively steep straight toe (shadows), flattens out in
the mid-range and steepens again in the shoulder (highlights). I did
my own testing of it on TMX though I have yet to use it in the field.
Phil showed prints (albeit RC silver prints) made by our own Sam Wang
of negatives developed in DI-13 compared to the same scene developed
in a conventional developer (don't remember which). While the
conventionally developed negative printed with muddy shadows as one
might expect from a radical contraction, the DI-13 negative printed
with excellent shadow and highlight separation and compressed but
luminous mid-tones. I think there is an article about this developer
in a recent issue of Photo Techniques.
Keith