Exposure, density, development & printing

[noseoil]

Without the use of a densitometer, I'm wondering about this one. I saw a curve once (sorry, can't remember where) which suggested that adding exposure simply moves the location of the entire film curve up. It increases density (print time) but does not affect contrast. I hear in some threads that adding exposure causes high values to "pile up" on the shoulder. With azo printing, added density seems to help with tonality. I've seen some very inky negatives for azo printing, so thick that you couldn't print through them without arc lamps. No chance of enlarging with them at all.

I know there needs to be enough density for shadows, but which theory is correct? Does it depend somewhat on the film? Does it depend on the exposure solely? Can anyone help with an explanation here? Thanks, tim

 

[Roger Hicks]

Dear Tim,

Adding exposure does indeed move the useful exposure range up the film. This is how the original 'first excellent print' research worked. People were asked to choose the first pair of prints where there wasn't a big difference between the print from the neg with less exposure and the one with more. The simple truth is that quality falls off a cliff with under-exposure, and remains good or excellent over a long range with over-exposure.

Yes, when you hit the shoulder, there are problems, but depending on the film, a stop or two or even three of over-exposure will rarely take you onto the shoulder except with subjects that have a VERY long brightness range.

The arguments in favour of minimum exposure, on the other hand, are as follows:

1 Shorter shutter speeds for better action stopping/reduced camera shake
2 Smaller apertures for more depth of field
3 Smaller grain (except with chromogenics)
4 Better sharpness
5 Better tonality by matching the toe of the film curve to the paper curve

The first four are indisputable; the fifth is rather more of a matter of opinion.

Cheers,

Roger (www.rogerandfrances.com -- and you might find the Photo School on that site interesting)

 

[Kino]

Tim, I also think it depends upon the gamma curve your developer, stock, time and temperature tend to produce; that's a huge factor to consider as well.

I guess what I am trying to say is, yes exposure pushes the useable range of the exposure up the gamma curve, if that curve is almost vertical, you have damn little room to maneuver before you brick wall on the shoulder.

Sorry if I am stating something obvious here...

 

[Roger Hicks]

Tim, I also think it depends upon the gamma curve your developer, stock, time and temperature tend to produce; that's a huge factor to consider as well.

Dear Kino,

You are of course absolutely right but with anything approaching a normal gamma (0.70 or below) it should not matter very much and even with very steep gamma (over 1.0) I find that an extra stop or even two doesn't 'blow' highlights on FP4 or Commercial Ortho.

Cheers,

Roger

 

[Allen Friday]

There is an interesting discussion of this very topic in "Way Beyond Monochrome," at pp. 141-145. The author reviews the study by Loyd A. Jones Roger refered to above. He then goes on and does a small scale sample of prints to see if the maxim "when in doubt, film should be overexposed and underdeveloped" still holds. He concludes that it does.

He has examples showing how a print from a negative with one stop over exposure (Fig. 2b) prints well, with only a slight correction to the papers contrast.

He does tie into the equation that the overexposed negative should be underdeveloped, however. He concludes, "the advice from the old masters of overexposing and underdeveloping film, when in doubt, has proven to be sound. This technique insures plenty of shadow detail, high local contrast and apparent sharpness." p. 145.

 

[juan]

And, of course, Mortensen argued that one, for enlarging, should underexpose - or at least expose the minimum necessary - and extend development. He argued that overexposed, underdeveloped negatives were good only for contact prints.

As with all, YMMV.
juan

 

[Allen Friday]

Hi Juan,

I was wondering, have you ever tried Mortensen's exposure and development system? I read about it a few years ago where he explains it as "expose for the highlights and develop for the shadows." I think it is in "The Model" where he gives the example of taking the meter reading off the brightest spot on the model's forehead, and then give the film as long a development as possible with out the emulsion coming off the film, even going to the extreme of putting the film and developer in the refrigerator.

In "The Edge of Darkness", Thorton explains what Mortensen was doing in zone system terms. It sounded interesting, but I have never followed up on it to see the results. Have you done any experimenting with it?

Allen

 

[juan]

Hi Allen,
I have not done much experimenting with Mortensen's method in the past, but I intend to. I brought myself up in the Cult of f/64 and considered Mortensen a heretic, but lately I've come to question everything I've done photographically. I'm telling myself it's because my eye has gotten better. Ha.

Fred Picker wrote a lot about setting his exposures based on Zone VIII rather than Zone III (or II). Some folks say his prints began to suffer after he made the change. I have not seen any of his prints, so I can't comment, but I know several people on this forum knew Fred and saw his prints. Any comments?

And what about Mortensen? Anyone actually see a Mortensen print who can comment?
juan

 

[Gerald Koch]

Mortensen was able to get away with his very unorthodox methods because his prints were highly manipulated. For example, he was not adverse to actually removing some portions of the emulsion or to adding to other portions with pencil or other pigments. Whether the result is a photo or something else is a matter for argument.

 

[Allen Friday]

Thanks for the reply, Juan.

If I remember Picker correctly, when he was using the highlight for exposure, he would read the highlight with his meter and then adjust 3 stops, placing the metered highlight on zone viii. My reading of Mortensen is different. I got the impression that he would meter the highlight and use the indicated exposure without adjustment. If I understand this correctly, Mortensen was giving 2 or 3 stops less exposure than Picker would have for the same scene. But, like I said, I haven't read this stuff in a couple of years, so my recall on it may not be 100 percent. I'll try to reread this over the long week end.

It would be fun to play around with, however.

By the way, if you like Mortensen, (which I do) check out "Monsters and Madonnas". The monsters and madonnas of the title are not the subjects of his photography, but are symbols for art and the machine.

I had an interesting talk with a photographer out in California last year about Mortensen. I commented that Mortensen may have lost the battle with the f64 group, but he may yet win the war.



Allen

 

[Donald Miller]

Since Tim specifically mentioned Azo as the material, I will comment on my experience with exposure, development and printing with this material when I still used it.

First of all, Azo requires a negative that exhibits a density range of 1.65-1.70 in order to print properly for the newer grade two material. Thus as I listen to people who seem to try to emulate the words that some people have used, they translate this to mean a negative that is very dense. They gain this overall density by overexposing the film, in many cases by as much as three stops or more. (Exposing the shadows on Zone III translates to two stops of overexposure if the film is rated properly. It relates to three stops when someone derates the film by one stop due to the latest rumor du jour.)

I think the logical beginning place in any and all photographic printing must begin with determining the characteristics of the material on which we are printing.

This over exposure gives a lot of added and in many cases counter productive density. Then when one attempts to gain the required density range (1.65-1.70) the high densities are compressed onto the shoulder of the film because very few films have the ability to expand contrast ad infinitum.

So what is the benefit of over exposing the film by the normal three stops? The advantage is one and only one from where I view matters. That advantage is that the low values are moved up on the straight line portion of the film's curve. This will provide better shadow tone separation. The hazard, in over exposing, is that you have only so much straight line to work with. This becomes especially problematic for printers of Azo, Pt Pd and some of the other processes.

Now, granted, with conventional silver printing...using current graded and VC materials, you can screw around with things and still be in the ball park relatively speaking.

The bottom line, as I see it once the paper's characteristics are determined, is the density range of the negative. That means in silver printing that if I have a DR of 1.00 or thereabouts that it will print just as well as if I have ruminated, tested, and reruminated on the Zone I and Zone VIII density...in many cases it will print easier and better.

 

[Allen Friday]

Donald,

I agree with a lot of what you said above. I think a trap many photographers fall into when trying papers with extended exposure scales is that they take their film speed from their silver tests and just extend development. Depending on the film, this may or may not work. Certainly, you will end up with a very dense negative that has a lot of wasted density and your print times will be very long. For platinum, you may end up with an hour or longer print times. That is why it is important to do the tests with the paper you intend to print on.

If you are using BTZS, the process involves a paper test and a negative test--reading the results on a densitometer and calculating the film speed for the film on that paper. You will of course still have to go out and do your field testing to verify.

If you are using the zone system, without a densitometer, you will need to do a new set of tests on the new paper. For the purposes of this discussion, I am reffering to using the methodology laid out by Fred Picker in "Zone VI Workshop", by Johnson in "The Practical Zone System" and most recently by Steve Simmons in "A Simple Way to test for Film Speed and Developing Time," in View Camera Magazine, January/February 2006. References will be to the Simmons article, given that many APUG readers will have ready access to this article.

Doing a zone system test this way involves three steps: 1. finding the proper proof time (pp. 45-6), by taking your chosen paper and finding the minimum printing time by printing a b+f negative; 2. Finding your personal exposure index (p. 46) by exposing negatives and then printing them to find the one that gives you "a tone on the paper just perceptablly lighter than the paper's maximum black." (p. 46) By knowing which negative prints this way, you determine your personal exposure index of this film specific to this paper; 3. Finding your normal development time, by exposing negatives at the paper specific EI and seeing which prints "just perceptibly darker than pure paper white. (p. 46) This will give you the normal development time for this film, specific to this paper. Once you have the above, you will still have to field test.

If you are using the "expose film and adjust" method, you would go out and expose a normal scene starting at the manufacturer's recommended speed and work down several half stops. The negs would then be printed on your chosen paper at your print time to see which one has the amount of shadow detail you want. That negative will give you your film speed for that paper. You would then go out and shoot the scene again at that speed and develop the negs at different times. The neg which gives you adequate shadows and detailed high lights will give you your development time. You still have to field test, of course.

The ZS, BTZS and "Expose and Adjust" will all get you to the same place: an exposure index (personal film speed) proper for adequate expose of your film for your chosen paper and development which assures adequate highlight detail on your chosen paper. The methods are different, but when done properly, the results should be the same.