ZS without densitometergreenspun.com : LUSENET : Large format photography : One Thread
Is there any other way to work with ZS without densitometer ? Thanks
-- Martin Kapostas (firstname.lastname@example.org), May 23, 2001
Well, you could always use the manufacturer's published data, which is obtained by using equipment and methodology far more accurate than most photographers have access to.
As long as you're willing to use one of the recommended developers, Kodak issue development times for nearly all their B&W material to give 'N', 'N+1', and 'N-1' curves. See, for example, email@example.com), May 23, 2001.
"Oops, I'll try that again. Well, you could always use the manufacturer's published data, which is obtained by using equipment and methodology far more accurate than most photographers have access to.
As long as you're willing to use one of the recommended developers, Kodak issue development times for nearly all their B&W material to give 'N', 'N+1', and 'N-1' curves. See, for example, Tmax 100 characterisitics.
Some of the world's finest photographs have been taken by photographers who totally ignored the zone system, and who openly admitted to knowing very little about sensitometry. Read the biography of Dorothea Lange for a case in point.
-- Pete Andrews (firstname.lastname@example.org), May 23, 2001.
There are a couple of approaches you could take. One is to build your own densitometer using a spot meter. The plans are contained in Davis' "Beyond the Zone System." Secondly, you might take a look at Chris Johnson's book "The practical Zone System." He includes a series of tables showing film/exposure/development combinations. Many of these deviate from manufacturer's data and provide a starting point for your own testing. Third, I believe that Darkroom Innovations provides a testing service to determine your own personal film speed (see http://www.darkroom-innovations.com). I hope this helps.
-- Dave Willison (email@example.com), May 23, 2001.
Martin, Many of us have been practicing the Zone System, or variants thereof, for years without ever having once used a densitometer. I sometimes think that the densitometer actually gives less usable data since it doesn't take the paper you are using into consideration.
The basic method is this: You test film speed and development time by exposing the film and developing as you usually would, but instead of using the densitometer and the attendant number values, you make "proper proofs" on the paper of your choice.
A proper proof is generally considered to be one that renders the clear portions of the negative (film base+fog density) at maximum paper black with the least exposure. You find this by making a test strip from an unexposed, but developed and fixed (i.e. clear) negative, letting it dry completely and choosing the minimum exposure time needed to produce the maximum possible black.
In practice it's not quite that simple, since small differences in black can almost always be seen even past the point one would choose as a usable maximum black, however, you can safely choose one of these deep blacks and use that as your standard.
After this, you use the same lamp intensity, enlarger head to baseboard distance, f-stop and exposure time for all tests with this film unless the development time varies more than about 20%, in which case you need to determine a new "proper proofing time".
Now, all Zone System calibration tests can be done by proper proofing the test negatives. Zones values are there for you to see and visually evaluate, and differences in curves and gradation are easily seen.
For a good source on this, get "The New Zone System Manual" by Minor White et. al.
Sorry this is so long, but there is a lot to describing this, even if it is not that difficult in practice. Hope this helps. ;^D)
-- Doremus Scudder (ScudderLandreth@compuserve.com), May 23, 2001.
I agree with Doremus. I started out trying to calibrate everything with a densitometer and was quickly becoming a tech head instead of an artist. I believe it is much more important for your negatives to print the way you want them to on the paper of your choice rather than arriving at some predetermined density. A more recent and excellent description of how to do all this without ever touching a densitometer is in Bruce Barnbaum's book, The Art of Photography: An Approach to Personal Expression. The book is a wealth of information and techniques that if followed will make your prints glow. His certainly do.
I have been a biologist and research scientist in aquatic biology for nearly 30 years,so I have some skills in dealing with technical stuff. I have read all the standard stuff on the Zone System (Adams, White, Picker, etc.) With that in mind, I have to tell you that Beyond the Zone System is way more information than most anyone would need and it is not the first book someone should read on the Zone System. I occasionally read it when I can't sleep.
-- Paul Mongillo (firstname.lastname@example.org), May 23, 2001.
Doremus hit it right on the nail. In a general and non detailed explanation, this is how I approuch the ZS. First let me say that I am A self taught landscape photographer. From the moment I see a vista in front of me , to the moment I look at the final print, every thing in between is tied together.
As a starting point , I try to land close to my film's density threshold by simply reducing the manufactures (iso) rating in half. Secondly, I find max black of the paper I will be print on. This BTW, is the glue that binds the whole process together. The Proof. I place my unexposed and developed negative (B+F), in the neg. carrier. I project the light to the same print size I will be using.
I first burn a maxium black guide print. I mark the enlarger hieght and begin exposing independent time sequences. Another words if I want a 3,6,9,12,15 I expose each one at a time. I take these test prints and give them a couple of minutes in the microwave. I want that first shade of dark that matches my maxium black test print.
Now, I expose a negative at zone 1 at the 50% rating iso I mentioned above. I place in the enlarger and give it the numbers that gave me max black, minmun time. What I am looking for now is the first shade of black going the other way toward a lighter shade. If it is , then I keep that iso film speed, if not I tweek the iso one way our the other. Remember what I said about everythig in between. What I did here is place (sinc'd)my film's threhold along side my papers.
Lastly, for the real World zone 8. Using your same film and iso as before go out side, meter on a big fluffly white cloud (the way you visualise a be white fluffly cloud should) and expose it in zone 8. I expose about 4 or 5 negatives the same zone 8. I then develope each one at different times before and after the recommended time. I place these negatives in the enlarger using the same proof time I just created. Now when I turn on the lights and see the one that gives me my big fluffy white clouds.
Then Presto! I now have my normal Negative always using my same processing,paper size,film ect. What ever you point that 1 degree on you will feel confident that what you visualise is that zone , will be that way on the final print. Did I ever mention the word densitometer even once?
-- Dan Kowalsky (email@example.com), May 23, 2001.
Here is another good description how to do it without densitometer:
-- Andreas Carl (firstname.lastname@example.org), May 23, 2001.
I think that one should at least attempt to obtain the film speed by finding the ASA so that a Zone 1 measures at 0.1 above film base plus fog. This requires a densitometer, and one can ask a lab, a friend, a professional, or someone to obtain this data. This, and the maximum black exposure time provides a good foundation on which to build. The remaining steps can be accomplished by evaluating and comparing exposures on paper at maximum black.
a) Determine "N" by finding the development time that gives a good Zone 8. (For me, this is where the texture, while not full, is detectable. The whitest portion of puffy clouds is probably close.)
b) Determine "N-1" by determining the development that makes a Zone 9 have the apparent density on the print as a Zone 8 at "N". This can be accomplished by comparing test prints.
c) Determine "N+1" by determining the development time that makes a Zone 7 have the apparent density on the print as a Zone 8 at "N".
I use a frosted piece of glass mounted on a black board with a 6" hole and place a "blue" daylight bulb behind this glass to achieve the different zones. Sometimes the light is placed well behind the frosted glass to obtain the lower zones.
So, I guess I recommend a workable compromise on this issue. Even if one has a densitometer, one should never depend solely on that device to obtain all development times. In my opinion, "N" always begins with a visual interpretation and decision of what they want for a Zone 7 or a Zone 8. Thereafter, one uses the densitometer only as an aid to determine if the Zone 9 negative matches the Zone 8 in "b)" above, to determine if the Zone 7 matches the Zone 8 in "c)", and so on.
-- neil poulsen (email@example.com), May 23, 2001.
It simply is not the negative that hangs on the wall. It is the print. For that reason you MUST make negatives that will print on the paper you wish to use. Also realize that black at grade 1 on a VC is not the same as black at grade 4. You need to have a mix of the emulsion on the paper and not be at either extreme. The negative needs all the information you require, but exactly where that falls on the scale will be determined how it prints on the paper. For these intertwined reasons, you simply create a negative to a predetermined scale of values and expect it to print how you want without including the paper in the scheme of things. Printing paper and the contrast, along with the look of the paper at each contrast, has a far greater impact on the image than slight changes in the negative. Besides, you are all the densitometer you need. You have to be able hold the negative up to an even light, like the blue sky, and be able to see anything you want to print. If not, then you have a problem at either end of the scale. Plus and Minus changes are never perfect, nor do they need to be. They help, but personal selection of values is not an exact science. Remember, Edward Weston didn't even use a light meter. So, you are already way ahead of the game.
-- E.L. (firstname.lastname@example.org), May 23, 2001.
To suggest that one only needs to be able to see the detail that they require on the negative in order to obtain the photograph they want discounts the fact that the negative can retain more information than the paper is able to print. It's also necessary to match the detail (in the negative) that one requires on the final print to the paper that they've selected. I know that I've always had bad luck relying on paper grades to pull the proverbial rabbit out of the hat.
The zone system is an ingenious system to transfer the image onto a negative in a way that the photographer can best achieve his or her visualization of the final print. A densitometer is a useful tool that allows one to better and more easily accomplish this task.
As to Edward Weston, he used an emperical approach that relied on years of experience in the field taking how many thousands of shots in determining his exposure strategy. Using a light meter in conjunction with the zone system enables us to achieve a personal exposure strategy in far less time.
-- neil poulsen (email@example.com), May 23, 2001.
Treaditional zone system testing is a pain, with or without a densitometer. Phil Davis' system as explained in his book "Beyond the Zone System" is far simpler and much more accurate. For approximately $30 The View Camera Store (formerly Darkroom Innovations) will do everything for you with whatever film (or films) you like. They send you five sheets of whatever film you wish to test, exposed with a 21 step wedge. You develop the sheets for 4 minutes, 5 1/2 minutes, 8 minutes, 11 minutes, and 16 minutes. You return the developed film to them and they take the readings with a densitometer, plug the readings into Phil Davis' plotter program, and send you the resulting information so that presto you have everything you need to use the zone system without the time, expense, and general hassle of old fashioned methods of testing. I'd strongly recommend letting them do most of the work for you so that, among other benefits, you don't have to worry about not having a densitometer.
-- Brian Ellis (firstname.lastname@example.org), May 27, 2001.