Wrote Peter Leyssens:
>Again, a summary :
---------
>3) Shawn : I should get myself a copy of The Negative. I can feel it in
>my toes that this is a book I'm going to learn one hell of a lot from,
>but at this moment, those Roman figures are driving me nuts.
If you can find it, R.J. Henry, Controls in Black-and-White Photography
(2nd ed., focal Press, 1986) is a better choice. St. Ansel got lots of things
wrong (including the entire Zone System) but Henry debunked lots of
traditional darkroom nonsense. He was a scientist with a scientific mind.
>5) Lars : 'grain like macadam', got to remember that expression. If I
>understand Gene correctly, the grain doesn't get larger, only more
>noticable. Or is it really possible to get a "Single-Grain Negative"
>(tm) ?
I cannot at all agree with Shawn's statement that grain is determined
in manufacture. Undeveloped film does not have any grain at all, only
microscopic halide crystals, invisible except under magnificatiuons
above 50--100 X or more.
As I stated before, films tend to more or less graininess, usually (but
not always) more the faster they are. Grain is flocks of metallic silver
reduced out in development. Its size is also to a very large extent a
function of how far the development process is allowed to go (time,
temperature, agitation). The nature of the developer also helps to
determine, not only the 'sharpness' of the grain but also the size, as
silver solvent (usually sodium sulphite) eats away at the edges of the
silver flocks. Simultaneously, dissolved silver can precipitate as smaller
grains between the large ones, filling the gaps.
I have been developing film since the 'fifties, in most developers known
to man. I have been a steady Tri-X user, developing both in Rodinal and
in 'fine grain compensating developers' such as D-76. Some years ago,
I wanted to use TMax 100 in my OMs for landscape work during a long
solo hike in Lapland (see my links page at
http://www.bahnhof.se/~timberwolf/english.html ). I wanted a method
to reduce negative grain. The developer was TMax Developer.
First, I tried the classical method, more exposure and less development,
the technique which in the 'thirties led to modern compensating developers.
Fine, but development times became too short to be controlled. So I diluted
the working solution 1 + 1 with plain water. That lengthened the time OK,
but the negs were extremely flat. I surmised (correctly, as I found later)
that the cause was the drop in alkalinity; TMD is very sensitive to that.
I hit on the idea of diluting not with plain water but with a 10 percent
sodium sulphite solution. Bingo! Very printable negatives, but the grain was
so fine that it was nearly impossible to focus the enlarger on it ... The
superstition that grain is ordained once and for all by the film manufacturer
is an ancient but not a venerable one.
>6) Lars : Thanks for mentioning the pre-exposure ! There are tricks
>like that that I have forgotten (because I only knew they existed and I
>never tried them).
Please note that pre-flashing or 'post-flashing' will decrease negative
contrast.
I have often used this flashing trick in order to tame the contrast of printing
papers. With the neg in place, I held a piece of matte drawing acetate film
under the enlarging lens and gave the paper a diffuse pre-exposure of about
1/3--1/2 the normal exposure time (same f-stop of course). That usually
did the trick.
Gene's notes are very correct. It is true that development stops earlier in
the low-density shadows than in the dense highlights where it can continue
until they have been completely blocked up. This is the rationale behind my
recommendation about the chromium intensifier. Then you can stop the
development at a stage when contrast is still controllable. The intensifier
does not bring out more shadow details, but increase their density above the
base+fog so that they do not print on the toe of the paper's curve.
The reason why Kodak does not publish true ISO speeds is that ISO-specified
development of the test strip would not produce a very printable neg., just
as Gene suspected. Have you noted that color films do not have true ISO
speeds either?
Vänliga hälsningar/Best regards
Lars Bergquist
Välkommen till/Welcome to ...
<http://www.bahnhof.se/~timberwolf/>
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