Traditional theory of exposure and development and variable contrast paper

[John Bond]

Historically, the concepts of exposure and development can be reduced to a few basic principles. “Expose for the shadows, develop for the highlights”. We establish film speed or EI based on how much exposure is required to create an arbitrary density above film base plus fog. We determine development time based on fitting the subject brightness range onto paper of a certain contrast. The discussion of establishing EI, metering technique and how much time to develop largely applies to the use of graded paper rather than variable contrast paper. While over the years, I have spent a lot of time trying to get my hands around all of this, the reality is that I use variable contrast paper much more than graded paper and either because it doesn’t matter or I am too lazy, the finesse required to maximize results on graded paper seems to go out the window with variable contrast paper. I have a general idea of my film speed and meter off of a dark shadow area with detail and take off two stops. I tend to fudge exposure a little in the direction of over exposure and my guess is that if a proofed everything for maximum black, I would be surprised at just how much I tend to overexpose. I develop for a time based on what is in a published table and make some adjustments based on prior experience. Over time, I arrive at time that seems to work pretty well and use that time over and over again for a given film and developer. I then print on variable contrast paper establishing exposure for the highlights and adjusting the contrast filters for the shadows. So, I end up with what is usually an overexposed negative that hopefully is in the ball park development- wise and compensate for subject brightness range and what ever errors I have made with contrast filters.

My questions are, with all of this in mind, does using variable contrast paper really get me off the hook with respect to the established theory established for graded paper? How much does film development time matter when using variable contrast paper? Should development time vary with subject brightness range as it should with graded paper? Does the use of variable contrast filters change how to establish EI, and how to meter? Is there an optimum development time with respect to subject brightness range? Is there an optimum contrast filter? Is developing for a shorter time and printing with a higher contrast filter different, better or worse than developing for a longer time and printing with a lower contrast filter?

 

[Dali]

I don't see what VC paper has to do with film developing process... The aim of film developemnt is to get the information you want on the negative. Using graded or VC paper won't change anything on what is actually on the negative as paper can't show details which are not in your film.

But maybe I missed something?!

 

[Nicholas Lindan]

Compensating for development and exposure vagaries with VC paper isn't as straight forward as one would like.

The shape of the HD curve, and hence the local contrast, varies with different filtrations. You can not compensate negative contrast with variable contrast filtering - you can fit the extrema to the paper easily enough but you will find the other tones in the print can't be brought into line - or, if the scene and your interpretation are just right the tones will fall into line accidentally/on-purpose.

A discussion on the curve shape and local contrast of VC paper is provided on the Darkroom Automation web site:
http://www.darkroomautomation.com/support/appnotevcworkings.pdf

 

[ic-racer]

So, I end up with what is usually an overexposed negative that hopefully is in the ball park development- wise and compensate for subject brightness range and what ever errors I have made with contrast filters.

What is the definition of "over exposure" (rhetorical question)
Your negatives are not over-exposed. Everything you are doing is fine and the best way to do it as it is.

I teach people Zone system and "N" etc. development when they want to learn it, but for my own work I do it nearly exactly as you. Multigrade paper and dichroic head nearly exclusively since the 70s.

 

[Allen Friday]

In the old days BVC (before variable contrast), a photographer would choose a grade of paper on which to print their images. The photographer would then tailor her negatives so that the negative printed well on the paper. But, not all negatives matched the paper perfectly, even using the zone system. If the negative was flat, the photographer would take out a different grade of paper, in this case a higher grade, and print the image. Most photographers chose to print on grade 2 paper. They would use grade 3 for flat negatives and grade 1 for contrasty negatives. For negatives which fell between the whole grades of paper, the photographer would use a different paper developer or combine a soft and regular regular developer to reach an intermediate grade.

Along comes variable contrast papers. Today, a photographer will choose a grade of filter to print their images. The photographer will tailor her negatives so that the negative will print well on the paper at that grade. But, not all negatives match the paper perfectly, even using the zone system. If the negative is flat, the photographer will use a different filter, in this case a higher filter, and print the image. Most photographers choose to print with a grade 2 filter. They would use a grade 3 filter for flat negatives and grade 1 for contrasty negatives. For negatives which fall between the whole grades, the photographer will use a filter of 1 1/2 or 2 1/2, etc.

In reality, not much has changed. The difference is that BVC you needed a box of paper for each grade you wanted to print, now you only need one box of paper and a set of filters. The approach is the same. In the old days there were photographers who didn't really care at what grade their negatives printed. They just changed grades by getting out a different box of paper. Today there are photographers who don't really care at which grade they print. They just change filters and grab another sheet of paper from the box.

 

[John Bond]

Nicholas, thanks for the great article.

 

[Dan Henderson]

Not that I am any kind of expert, but it just seems to me that the goal should be well exposed and developed negatives, for several reasons. First, it is just good craft. Second, if in the process of shooting and developing a particular negative you do make an error, it is not compounded on previous overexposure and overdevelopment errors and you still may end up with a reasonably printable negative with which to work (I read recently that a "Murphy's Law" states that errors never happen in isolation.) Third, Aiming for a perfect negative gives you more room to dodge, burn, and do other darkroom manipulations for creative controls instead of using them to rescue a poorly exposed or developed negative. Fourth, overdone negatives require longer exposure times, and sometimes inordinately long burning times. Finally, doesn't overexposure and/or overdevelopment increase grain?

As I said, I am not an expert, but I contact print all of my negatives at minimum time for maximum black, and if the print does not seem "right" in terms of exposure and/or contrast, I start thinking about what the problem could be. I recently switched developers and found that the suggested developing times are too long for me and were resulting in overdeveloped negatives.

I hope this does not sound like I am railing at the OP. I am not, just expressing my opinion on this subject.

 

[David Lyga]

The problem here is the redundant 'need' to separate exposure from development. Sorry to state that exposure has a LOT to do with contrast - a lot more than theory readily tells (or most people want to think). Thus, 'how much to develop' becomes dependent upon this initial 'burning into the emulsion' with light. If you underexpose, your 'normal' development will yield a lower contrast negative. If you overexpose, your 'normal' development will yield a higher contrast negitive (but only UP TO A POINT before flattening out at the shoulder). (Here, 'overexposure' is defined as merely adding a bit to the minimal threshold established by ISO. Thus, contrast buildup is, initially, going to happen.)

The real problem stems from the diversity of scenes out there where, AESTHETICALLY, some, having the same contrast range, have different contrast requirements in order for the final print to make sense and impart meaning. Thus, sometimes shadow detail is not merely unimportant to register but becomes aesthetically necessary to omit. Sometimes, of course, otherwise.

The goal is to obtain a negative that will print easily and readily impart the aesthetic value you want. This negative just might junk 'theory' and be completely 'wrong' as far as the general textbook is concerned. I regularly cut off film from the camera just to process a few frames another way (different development, different exposure). It is amazing to behold that when you sacrifice shadow detail you open up highlights to greater separation and vibrancy.

Those searching for a direct, unified answer in this regard will simply be reiterating what hundreds of redundant textbooks have alreadly, and annoyingly, said before. Maybe David Vestal is NOT so ignorant after all in his 'Craft' book extolling the virtues of Tri-X at 100 or even 50!!!. There are indeed times when this overexposure is right. - David Lyga.

 

[BetterSense]

Especially with roll film, I don't get too fancy. I figure exposure is like nutrition...before you can get fancy, the first thing is you need enough. I expose using an incident meter or sunny 16 plus 'a bit for good measure'. I develop pretty much everything at the same time unless I know it needs a push or pull, then I add or take off a minute. Or two. Did I establish that with a densitometer? No, just what seems to print without too much work. I make proper proofs and if the image is so bright as to be hard to see I figure I overexposed. If it's so dark as to be hard to see I figure I underexposed. In either case they can usually still be printed to something. If the proper proof comes out so that I can see the subject and basically it looks like a picture, I find that I can make a good print in the darkroom from it.

Basically the point is that black and white negative film is very robust under exposure and development and especially for roll film, I actually find it pretty easy to arrive at decent negatives, after a loosened up my definition of decent to "makes a reasonably visible proper proof". Perhaps we can start a "merely adequately exposed and processed anonymous club".

 

[John Bond]

Dan, I agree with everything you said. I think the work flow that I describe above is fairly common and works much of the time. On the other hand, the convenience and flexibility of variable contrast paper seems to make it difficult to establish an optimum development time (as is done when the intention is to print on graded paper). Further, it does not seem that there is much out there describing a methodology to arrive at what is optimal development and optimum filtration for variable contrast paper.

Looking at the article that Nicholas refers to, it does appear that it is generally better to use less development (less contrasty negative) and a higher grade of filtration than to use more development (more contrasty negative) and lower grade of filtration to minimize the bumps in the curve that arise from lower filtration.

 

[5stringdeath]

Especially with roll film, I don't get too fancy. I figure exposure is like nutrition...before you can get fancy, the first thing is you need enough. I expose using an incident meter or sunny 16 plus 'a bit for good measure'. I develop pretty much everything at the same time unless I know it needs a push or pull, then I add or take off a minute. Or two. Did I establish that with a densitometer? No, just what seems to print without too much work. I make proper proofs and if the image is so bright as to be hard to see I figure I overexposed. If it's so dark as to be hard to see I figure I underexposed. In either case they can usually still be printed to something. If the proper proof comes out so that I can see the subject and basically it looks like a picture, I find that I can make a good print in the darkroom from it.

Basically the point is that black and white negative film is very robust under exposure and development and especially for roll film, I actually find it pretty easy to arrive at decent negatives, after a loosened up my definition of decent to "makes a reasonably visible proper proof". Perhaps we can start a "merely adequately exposed and processed anonymous club".

I agree that a lot of discussions I read, and learned from, regarding exposure and development are quite relevant when shooting sheet film, and to some extent to shooting 120 or 220 MF where you can be quite consistent over a roll. But being a 35mm 36exp shooter for most of my life, a lot of the "rules" or "guidelines" have to be loosened up ... 36 frames are a lot to consider and unless one takes notes by exposure for every frame (which I do not) then its hard to get every negative "perfect" (whatever that means.)

Then again, I think that's part of the joy of shooting 35mm ... the occasional beautiful mistake, the shot you couldnt miss but the exposure was off from the rest because you were rushed, finding one of your cameras 6 months later with 1/2 roll of shot film. Its just another sort of magic. I'm still excited when I process film and after the fix, pulling the reels out of the tanks and seeing those rectangles -

I also believe this method has made me a better printer overall. I can read my contact sheets very well now. "These negs are fine" (so, say, Grade 2) "This neg will need a #1 filter" ... I can very much understand my film, knowing full well WHY different negs look different ways ... and then, in the future, I can apply those things purposefully.

That said, I'm glad I was raised in photography by knowledgeable teachers and colleagues who introduced me to the Zone system, N development techniques, exposure tricks and tips ... and also being told they are harder to apply shooting roll film.

I like being a kind of "loose" shooter, but that in no way means I don't know what I'm doing nor that I take care in taking meter readings (I still mainly use a handheld meter, unless I'm on the fly street photographing). And when I teach classes, I do the same thing for my students that was done for me. Same old adage ... its good to learn the rules so you know whats happening when you break them - or ignore them - or figure out they aren't really rules after all.

And I use VC paper now almost purely for economical purposes. Not that I can't afford graded papers, but I prefer to work from one box. Of course I have about 4 different boxes of different papers, haha.

 

[Mahler_one]

John: Regarding the less development and less contrast in the negative, etc.: Such approach was pretty much the approach suggested by Phil Davis in his BTZS text.

 

[Allen Friday]

On the other hand, the convenience and flexibility of variable contrast paper seems to make it difficult to establish an optimum development time (as is done when the intention is to print on graded paper). Further, it does not seem that there is much out there describing a methodology to arrive at what is optimal development and optimum filtration for variable contrast paper.

John,

I really don't understand your problem here. Variable contrast paper is just that, using one box of paper you can produce prints at varying contrasts depending on the filtration used. One box of paper can produce grade one prints with one filter, grade two prints with another filter and grade three prints with a third filter. You can do the same thing with graded papers, but you must have a different box of paper for each grade. With graded papers, you change paper, not the light. With variable contrast paper you change the light (filtration) not the paper.

The concepts in printing are the same. You start with the grade of print you want--e.g. grade 2 graded paper or grade two filtration with variable contrast paper. You then test your materials so that you expose and develop your negatives to print consistently at that grade. The goal is that each negative will print well at that grade. In real life, that goal is difficult if not impossible to reach. You then use different grades (either of paper or filtration) to make the best print possible from the negative. If you wanted to use grade two, but the print is flat, you will dial up the filtration to grade three, or use a graded grade 3 paper.

You state that there is no optimal development and no optimal filtration for variable contrast paper. This is a bit confusing because it is not clear if you are talking about the negative or the paper. I will address both. 1. Paper. There is no optimal filtration for VC; but there is also no optimal grade for graded paper. You as the photographer have to decide which grade you want most of your prints to be at. Most photographers shoot for a grade two or grade three. Once you have selected the grade, that becomes your optimal grade for the paper. You then obtain that grade by using either graded paper at that grade or by setting the filtration to that grade on you enlarger. 2. Film. Once you have decided on your optimal grade, it will not change. Grade 2 variable contrast or grade 2 graded will not matter (except to the way the tones are rendered differently by the different types of paper--the over all exposure scale of the papers will remain constant.) You then test your film so that you consistently expose and develop the film to that contrast. That will be your optimal film exposure and development for grade two variable contrast paper. When printing, you would start by printing each negative at grade 2. If the print looks good, you are done. If it is flat, you increase the filtration to up the grade.

Basically, you need to treat variable contrast paper as if it were graded paper. Conceptually, there is no difference between moving from a grade 2 graded paper to a grade 3 graded paper and moving from a grade 2 variable contrast print to a grade 3 variable contrast print.

 

[RalphLambrecht]

Not that I am any kind of expert, but it just seems to me that the goal should be well exposed and developed negatives, for several reasons. First, it is just good craft. Second, if in the process of shooting and developing a particular negative you do make an error, it is not compounded on previous overexposure and overdevelopment errors... Third, Aiming for a perfect negative gives you more room to dodge, burn, and do other darkroom manipulations for creative controls instead of using them to rescue a poorly exposed or developed negative. Fourth, overdone negatives require longer exposure times, and sometimes inordinately long burning times. Finally, doesn't overexposure and/or overdevelopment increase grain?

As I said, I am not an expert, but ...

Dan

You sound like an expert to me!

 

[John Bond]

I apologize if my questions are confusing.

I would agree that using variable contrast filters and using multiple grades of paper are similar in many ways, but both are different than using one grade of paper and adjusting development time to correspond to the subject brightness range. Using one grade of paper and adjusting contrast through development is at the heart of the Zone system and its variations and is what a lot of us have learned from way back when (I have been doing this for over forty years now). Using the Zone system and varying development works best for sheet film and is not as convenient for roll film although it can be used for roll film if the subject brightness range is similar for the whole roll. So, most of us who use roll film develop for a given time and adjust contrast with variable contrast paper or multiple grades of paper. This is fine as far as it goes and is certainly very forgiving, but I am not convinced that it is the best way. I am not convinced that we obtain the same results with less development and higher contrast filter or (higher paper grade) as with more development lower contrast filter (or lower paper grade). So, why not vary both development time and paper grade/contrast filtration if it were to achieve a more optimal result ? Is there a rigorous way of finding what is the optimum combination of development and paper contrast rather than picking some arbitrary development time and later adjusting contrast by changing grade of paper or contrast filtration?

 

[Chazzy]

You're making this way too hard. Just shoot for a negative that will print well on grade 2, like everyone else.

 

[John Bond]

If I wanted it to be easy I would shoot digital

 

[Chazzy]

If I wanted it to be easy I would shoot digital

In that case, I recommend switching the developer and the fixer.

 

[John Bond]

Chazzy, I'm sorry if I offended you. I did not intend to.

 

[Allen Friday]

John, you keep bringing up "optimal result." Can you define that for us? Perhaps if we know what you are striving for, we can advise how to get there.

 

[RalphLambrecht]

If I wanted it to be easy I would shoot digital

I want to shoot digital too, but the stupid thing doesn't sit still long enough.

 

[RalphLambrecht]

Being more serious:

Compensating for subject contrast through film development is very similar to compensating for negative contrast with variable-contrast (VC) papers. Not the same but very similar. This does not mean that VC papers have replaced the Zone System altogether. The Zone System delivers a perfect negative, and VC papers are very tolerant of less than perfect negatives. But, when used to get the most out of a mediocre negative, VC papers do not always have enough room to adjust for local image-contrast needs. However, when used together, Zone System and variable-contrast papers provide more creative flexibility than either one possibly could alone. For a fine-art printer, this is not an either/or decision. Both are powerful tools in their own right.

 

[John Bond]

Allen,

Thats a great question. And, I am not sure I can put my finger on it. Maybe it is as much about knowing what the differences are as much as what is optimal. The paper that Nicholas offered suggests some ideas that make sense with things that I have observed. Prints from lower contrast filters frequently seem to have muddy shadows and no sparkle in the highlights and with extreme yellow filtration, it is hard to get as dark a black. So one point of optimization is what combination of the two or three emulsions in VC paper gives the darkest black. My guess is that it is usually somewhere in the middle and not at either extreme. The other is how to maximize contrast in the mid shadows and mid highlights. Based on the article, it may amount to simply knowing how much yellow filtration you can give before the bumps in the curves start to appear and stick to filters above that level.

 

[John Bond]

Great point Ralph.

 

[Nicholas Lindan]

The curves for a few paper/developer combinations are also on the Darkroom Automation web site:

http://www.darkroomautomation.com/support/index.htm

Some are not pretty to look at, example: