Archived posting to the Leica Users Group, 1998/01/06

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Subject: Re: [Leica] T400CN and gradation
From: "Henning J. Wulff" <henningw@archiphoto.com>
Date: Tue, 6 Jan 1998 00:09:37 -0800

Pete Myers wrote:

>Perhaps I just have not found the magic touch with T400CN. Perhaps other
>Lugnuts have had better luck or technique.

I have to say that I'm not too pleased with the T400CN or, for that matter,
XP-2. I use them when I have to take record shots in B&W, and for
commercial assignments under difficult lighting conditions (which they are
excellent for) and when archival permanence is not a primary concern.
Often, of course, clients want B&W primarily for the proven archival
qualities.

I don't generally find the negs hard to print, but the density slope is
'wrong' compared with regular B&W material. The fact that you can expose it
from EI 50 to 400 means that the slope has to be pretty much at the same
angle all the way up, without much of a toe or shoulder. Silver negs with
standard toes and shoulders require more precise exposure and development,
but allow the highlights and shadows to be properly compressed so that the
midtones are spread out, while the extremes aren't. To get a decent black
with the chromogenic films, and a decent highlight, the midtones are left
with too small a share of the reproduceable gradations, and the print then
looks muddy. Maybe the answer is a paper which has the proper slopes built
in. Our paper is all designed for standard silver negs, rather than
dye-cloud negs. It shouldn't be too hard to design a paper that has the
proper characteristics; that would fix the gradation problem.

The second problem is not as fixable after you buy the film. The negs have
very poor acutance. That is, the graphing of the densities across a sharp
transition from very black subject to very light subject has rounded
corners. In regular B&W, with the right choice of developers, you can round
the corners off as well (solvent developers do this), have them sharp and
close to right angles (D-76), or even enhance them and have a slight
reverse kick (compensating developers such as Rodinal. Lack of acutance, or
rather the lack of possibility of high acutance bothers me; that's why
Kodachrome 64 (if I could find a reasonable place to process it) would
still rank ahead of any of the E-6 film in my estimation. Even though tests
show that many 100 ISO E-6 films resolve as much or more than K64, and
Velvia definitely does, K64 looks just as sharp as Velvia in most
circumstances even though it is not nearly as contrasty and grainier.

Come to think of it, Velvia also has a poor slope. Very steep, with a very
short toe so that shadows are inky black and lost forever. Please Kodak,
let's see some of those K-14 labs!

Anyways, enough of pleas to the Yellow Father, who is known to seldom
listen. I think in his old age he hasn't gotten used to wearing a hearing
aid :-).

So regarding the chromogenic B&W films, with the huge eposure latitude
comes the penalty of a strange density curve, and with the smooth dye
clouds comes the penalty of a lack of true crispness. Use the chromogenic
B&W films for those special occasions, or if you don't want to soup it
yourself, but for nice prints, use the old technology.

My 3 cents (about 2 cents US).


   *            Henning J. Wulff
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