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Ron Klein
Well, I have starting to apply the zone system concepts that I have been
studying and I think the results have been good. I have not yet
formally tested my effective film speed. The main reason being that I
confused about the actual technique. I read one book ("Introduction to
the View Camera" I believe) which described an emperic method of
essentially bracketing the exposures over several stops and then
eyeballing the result. I have just read BTZS and I don't see how he
arrives at ones effective speed.. I think I understand how he finds the
speed point, but how that translates to an actual film speed, I don't
see. Perhaps I have missed the point and the BTZS systems only defines
film curves and doesn't actually define the effective ASA of the film?
Please, Help. I wish I could find a course on this where I could
actually speak to someone about this.
C. W. Dean
A good text that gives a very straightforward procedure for what you're
asking is ZONE VI WORKSHOP by Fred Picker. Picker learned his basics in
workshops with Ansel Adams and others. His definition: "The proper ASA
speed rating is the one producing the minimum printable density of a
Zone I exposure. That density is .08 to .10 above 'film base plus
fog'."
He further defines 'film base plus fog' as unexposed but processed film
as found on the film edge or a blank unexposed piece of the film.
This minimum density value will vary widely among users because of
differences in equipment and methods.
--
Best regards & Good Photography!
C. W. Dean
Practicing Professional Photography since 1972
Further info: http://members.ebay.com/aboutme/seadub/
LoungeAxe
Your most accurate evaluation is going to involve the use of a densitometer.
You will find that there are many 'methods' out there in terms of arriving at
your working EI and processing times. Stick with one. My first experiences
with the zone system came with my purchase of Ansel Adams book The Negative. I
have pretty much lived by it since. It's straight-forward and it works.
Michael D. D'Avignon
Tim Daneliuk
>
> Well, I have starting to apply the zone system concepts that I have been
>
> studying and I think the results have been good. I have not yet
> formally tested my effective film speed. The main reason being that I
> confused about the actual technique. I read one book ("Introduction to
> the View Camera" I believe) which described an emperic method of
> essentially bracketing the exposures over several stops and then
> eyeballing the result. I have just read BTZS and I don't see how he
> arrives at ones effective speed.. I think I understand how he finds the
> speed point, but how that translates to an actual film speed, I don't
> see. Perhaps I have missed the point and the BTZS systems only defines
> film curves and doesn't actually define the effective ASA of the film?
> Please, Help. I wish I could find a course on this where I could
> actually speak to someone about this.
At the risk of irritating the film testers among us, I have an alternate
suggestion. I too began by doing a lot of film testing using a
densitometer. After a while, I began to realize that my tests were
remarkably close to what I was reading in the various zone books. A few
more years of experience and I realized that even the most rigorous zone
testing will only get you into the ballpark in any case: you end up
"tweaking" exposure and development for a particular scene and aesthetic
anyhow. Therefore, I recommend saving yourself a lot of testing and making
more pictures by using the following shortcut - no it is not rigorous and
you don't get to plot H/D curves or use logarithms ;-)
I should point out that I am a meticulous printer and make prints which
sell (occasionally ;-) for many hundreds of dollars. The techique I
describe below gives me great big fat negatives which are easy to print
and have lots of room for darkroom manipulations.
Assumptions
===========
You have an accurate thermometer
You have an accurate timer
Your commonly used shutter speeds are no more than 1/3 - 1/2 f-stops from
nominal. (This should be the case for any well-maintained shutter so
long as you don't try to use the fastest speed on a leaf shutter - these
are always out to lunch, even on a brand new Copal or Hasselblad shutter
in my experience.)
Your water supply does not vary much through the year - mine does, so I
switched to distilled water for mixing developer.
You have reasonable/repeatable lab technique. That is, you agitate
consistently, you replentish developer properly or use one-shot mixes,
etc...
What To Do Initially
====================
Expose the film at an EI 1 full stop slower than marked by the manufacturer -
ASA 400 film is shot at 200, ASA 100 film at 50, and so on. Pick
a subject which is typical for you. Just make sure it has a pretty full
range of shadows and highlight. An old building in bright sunlight is
my favorite - shadows under the eaves and bright surfaces on the walls.
Expose by place a shadow with some detail in it on Zone III. Check around
and see where a Zone VII highlight (with just a hint of detail)
can be found in the image.
Develop 20% *less* than the recommended time for the temp/agitation
recommended by the developer manufacturer.
Print using your usual paper and developer combination. For graded papers
start with grade 2, for VC, set up for grade 2.
Dry and flatten the print.
Judging the Results
===================
(This is very important...) Examine the print under a light intensity which
is close to the light which will be available when the print is displayed.
Ideally, you want to temporarily hang the test print on a wall where you
normally hang your prints.
If you found the "sweet spot", your shadow (which was placed on Zone III)
will have some noticeable detail and the highlight you previously
noted will also just have a bit of detail as well (say the blistering
paint on a wallboard is just visible).
If the shadow has too little detail for your tastes, decrease the EI by 2/3
stop and try again.
If the shadow has too much detail, raise the EI by 2/3 stop and do over.
If the highlight has too much detail - i.e., it is too dark - increase your
development time by 10%.
If the highlight is blown out - has no detail/pure white - decrease the
development time by 10%.
N+ and N-
=========
There was, no doubt, a time when very careful calibration for + and -
processing was necessary because the materials were so unforgiving and
limited. I don't think this is warranted as much any more. First of
all, modern film, properly exposed and processed, and handle north of 12
stops of dynamic range. It is my general philosophy to try to get as much
on the negative as possible and decide what part of the range I want
to use when printing. Moreover, the films I have used the most seem to
have a limited patience for N+ processing - you can squeeze N+1 out of
most modern films, but after that, the results are less than terrific.
Nonetheless, there is still a place for varying development time
because + and - process expand and contract the relative contrast between
the middles zones (IV - VI) in a noticeable way which can be quite pleasant.
Once you have established "normal" EI as described above, here's a good
starting point for + and - processing:
N-1: Rate the film 1/2 stop slower than your normal EI and develop 20%
less than your normal time.
N-2: Rate the film 1 stop slower than your normal EI and develop 40%
less than your normal time.
N+1: Rate the film 1/2 stop faster than your normal EI and develope 25%
more than your normal time.
Will these be "exact" - No, but then again you could test for 6 months,
calibrate everything to a 1/3 stop faretheewell and STILL end up tweaking
things to suit your aesthetic sese (which is WAY harder to develop than
film ;-)
There is absolutely a place for some testing and rigor here, but over the
years, I've learned that consistency, especially in exposure placement and
darkroom technique is much more important than quantitative analysis.
Try this. It works, and it will get you on your way to making pictures,
which, after all, was the whole point in the first place. If someone
complains that you are departing from the one true Zone Doctrine, ask to
see their prints...
Brian Ellis
asking about testing for effective film speed using Phil Davis' methodology
as set forth in his book "Beyond the Zone System." Assuming that is what you
were asking about, with Phil's system you don't test for or use an
"effective film speed" as you do with traditional zone system methodology.
It's been a while since I took his course and studied his book but if I
remember correctly the testing necessary to produce the curves that you
eventually develop and use with his system is done using the manufacturer's
rated speed.
If you don't have a densitometer or just don't feel like doing the tests
and working up the curves yourself, for about $30 Darkroom Innovations will
do most of the work for you. They will send you whatever type of film you
specify. The film will have been pre-exposed with a step tablet. You develop
it, send it back to them, and they will produce all of the curves and other
information you need. Otherwise you either do it by hand, which is very
tedious, or you buy the computer program which is nice because you can then
use it with all kinds of different films if you want to but the quick,
simple, easy way is to let Darkroom Innovations do it. Either way, you don't
do any testing for an effective film speed. Hope this helps. Brian
Jeff Schimberg
Picker has a 3 part video series available from Calumet. The one
titled "Fred Picker's Photographic Technique" shows how he tests for
film speed, etc.
On Thu, 04 Mar 1999 14:52:13 -0500, "C. W. Dean" <cwd...@erols.com>
wrote:
Lee Carmichael
approach the whole subject. One thing that you get out of testing is the rigor
of procedure and how the photographic process works. Doing the same thing in the
lab, all the time. Consistency is very important, I think. Experience is a
great teacher. For me, if I want to learn to play first base, I have to go get a
glove and stand out there and let people hit the ball to me. Same with
photography. Also, one of the great revelations is seeing the first really good
negative come out of the wash. That is mystical, if you ask me.
As usual,
Lee Carmichael
mailto:cl...@flash.net