> All Long Time Ago, before the digest blew up, AG made this
> intriguing comment...
Ok, so you're blaming the crickets on me? <smile>
> I have been getting back into the darkroom after a *loong*
> lapse, and
> feel like I'm struggling to get controlled, repeatable
> results. But I
> have a pretty good grasp of what happens to an image when you
> manipulate Photoshop curves. So I wonder if you'd care to
> expand on
> that comment--e.g. how do those techniques relate to
> squooshing the
> shape of a curve in PS?
Ok, I'll try. If the exacts are a bit off, don't shoot me,
because nothing about wet darkroom is exact. Change one element
such as the paper, temperature, chemistry, enlarger, etc., and
everything skews. Using these variations to your advantage is
what it's all about.
Generally, you have two main controls in darkroom printing:
Exposure and Contrast. You control brightness with exposure,
contrast with paper grade. Traditionally, you expose for the
highlights and contrast grade for the shadows. This technique
is fine if the negative and the paper have linear responses and
the negative was exposed with the mid-tone on Zone V (in a Zone
0-X range). Where this technique falls down is when your
mid-tone is NOT captured in Zone V and the film or paper
response is not linear. Which is most of the time. If you
expose B&W film like you expose 'Chromes, you'll be ok most of
the time.
But is exposure and contrast enough control? No. Typically you
have five points that you want to control.
1. Black Point
2. Shadow
3. Mid Point
4. Highlight
5. White Point
In the computer you are able to set the Black Point, Mid Point
and White Points easily with the Histogram/Gamma dialog boxes.
Shadow (Zones II-III) and Highlights (Zones VII-VIII) are
adjusted using the Curves dialog box. If only there were
equivelent "tools" in the darkroom to accomplish these same
tasks. Fortunately, there are.
1. Split Grade Printing
2. Paper Flashing
3. Chemistry/Development
4. Paper brand/model Selection
5. Local treatment for density gain or reduction
First of all, I must say that Split Grade Printing is the most
revolutionary darkroom technique in my lifetime. When I showed
my father the technique (my teacher), his jaw almost dropped on
the floor. It completely changes the way we print B&W. Ok, now
that I've got that out of the way. Let's look at how I approach
a challenging negative.
1. Trial print with standard Exposure and Contrast controls.
This gives me a working print showing me the White Point and
Black Points where I want them. Sometimes everything else will
fall in place, but most of the time the Mid Point is skewed
(needing gamma adjustment), the shadows are muddy (needing
density increase), and the highlights washed out (needing
suppression).
2. Trial print with a grade 2.5 (for my darkroom, YMMV), and if
the print yields a proper Mid Point, Highlight AND White point,
but the shadows and Black Point are weak, the negative demands
Split Grade Printing. (Skip to Step 7). Otherwise I'll use the
following steps.
3. Paper flashing. Paper flashing is a technique of exposing
the paper to just enough light to NOT produce any visible
fogging. You'll flash just below the theshold point. Any more
and your White Point depresses. The result of this technique is
to bring out detail (lowering by as much as one Zone) in washed
out areas of the picture. Clouds and waterfalls will gain
textures and gradients. This is EXACTLY like suppressing the
highlights in the Curves dialog.
4. Increased development. Sometimes you can bring a print just
to the point of proper exposure, but the Black Point just isn't
there. Increasing the development, high rates of agitation and
sometimes changing the dilution will be enough to increase
density by one Zone in the low levels. Highlight and Mid Point
exposure will not change very much. White Point will be affected
if your safelight is too bright. This is EXACTLY like moving the
Black Point to the right in the Histogram/Gamma dialog.
5. Every brand and model of paper has different response curves.
None are linear and how much they shoulder and/or toe will give
you minor equivelent control similar to the Curves dialog. The
amount of shoulder/toe is also dependent upon the chemistry.
For example: Ilford Multigrade in Multigrade Developer has a
noticable shoulder (highlight suppression) as compared to Forte
Warmtone VC. To achieve a similar shoulder with Forte, I've got
to flash the paper. Forte is a good paper if I need to LIFT the
highlight curve to add sparkle or "glow" to a picture.
6. Localized contrast control. Dodging and Burning are the
obvious tools here. But how about spot bleaching? How about
local density increase through light rubbing of the print with
your fingers during development or "dunk and remove" to suppress
development of shadows for extremely high-contrast negatives.
7. Split Grade Printing. Most of the time you can use the above
techniques--in fact, with grainy negatives you have to use the
above techniques as Split Grade will not work on grainy, high
accutance stuff. With Split Grade, you've got to use your test
prints as references to know what is and what is not there.
I've got a timer designed for Split Grade usage which tells me
my effective paper grade. Otherwise, it's purely guess work and
requires test prints to keep your sanity.
Split Grade 101:
This printing technique uses variable contrast printing papers.
These papers have two emulsion layers, each sensitive to a
different color light. One layer has a long exposure curve and
the other has a very short exposure curve. By exposing the two
layers seperately we can achieve dramatic results. (It's easy
to similate this in "Photoshop" with two a duplicate layer and
agressive contrast/brightness settings).
The Grade 0 exposure is used to expose the Mid-Point (just
slightly underexposed), Highlight and White Point. Paper
flashing, dodging and burning may be used where necessary. As a
matter of consistancy, I ALWAYS expose the Grade 0 layer first.
Completely ignore shadows and Black Point--that will come later.
Your only challenge will be with the Mid-Point as this can skew
a little once we do the second exposure. Don't try to burn in
anything that goes below Zone V (Mid Point). The Grade 0
exposure is the time to work Zone VI-X. Use every trick you
need to get this portion of the print correct. Do your test
prints without going on with the Grade 5 exposure.
The Grade 5 exposure is used to expose the Black-Point, Shadows
and add body to the Mid-Point. You can do a test strip of just
the Grade 5 exposure to get in the neighborhood, but otherwise I
see little value to doing it without the Grade 0 exposure
because once you combine the exposures the second one will
almost always be 1/2 stop overexposed. I recommend that you
expose *just* enough to set a Black-Point for the print. This
will usually leave some areas a little weak, but then you burn
in on those areas to add the needed density without the loss of
tonal seperation. If you overdo the Grade 5 exposure, your
mid-tones will go dark and muddy. Otherwise, Increasing the
Grade 5 exposure has the same affect as pulling the curve down
in the shadows area in the Curves dialog.
There are people who claim that you can Split Grade Print using
two similar grade settings, such as Grade 2 and 3. This would
give an affective Grade 2.5. This isn't true Split Grade
printing, but a technique to achieve mid-grade print results.
Since I've gone to a color enlarger head, I've never used this
technique.
I hope this helps.
AG-Schnozz
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