(for B&W Exposure and Development)
by Mike Johnston
Part I: Why Gray Card Readings can be Wrong
This four-part article amounts to my two cents about the black arts of metering, exposing, and developing black-and-white film. Doubtless you’ve read a good deal about this already, but even so, it's possible you’re still not quite all clear in every particular. Eventually, I’m almost sorry to say, I’m going to be proposing my own simple system for doing B&W right (every B&W guru worth his salt has to have his own system). But along the way, my ambition—and it is a lofty one, make no mistake—will be to make exposure and development a little more, rather than a little less, clear.
Photographers run the gamut when it comes to metering scenes and exposing and processing film. At one end are the good folks who buy a consumer camera they don’t really want to know how to operate, pop some film in, and let the camera read the DX code and set the film speed. Then they set the camera on the green square, or whatever that model’s “do-everything” mark is, and point and shoot.
At the other end are what are sometimes called “Zoners” or “Zonies,” an increasingly generic term for people who shoot single sheets of large format film (sometimes very large—one of my friends just bought an 11x14-inch camera) utilizing spot meters, little hand-held computers, copious notes, and testing with densitometers. At that end of the spectrum, there is a lot of spirited discussion as to what is really the most precise and accurate method of exposure. The granddaddy of these methods is the Zone System, but various experts have proposed a number of competing systems, some of which are even more rigorous and involved than the ZS. Phil Davis's "Beyond the Zone System" (BTZS) and Andy Eads' VIDEC are the best of them, if you want my opinion about that.
There’s nothing wrong with either extreme (except that they’re, uh, extreme). Whatever floats your boat, right? Or whatever yields the degree of control over your results that you need or want.
The innocent-seeming but ultimately treacherous gray card
Most methods of exposure and development, of course, fall at neither of these extremes, but in the middle somewhere.
Many of us, for example, have learned the hard way when and where our in-camera meters get “fooled.” The meter, we eventually learn, assumes a middle gray averaged subject luminance, and gives an exposure reading that will replicate this average. Trouble is, this otherwise excellent system goes awry when you’re photographing that polar bear in a snowstorm or black cat in a coal mine, because the subject isn’t middle gray.
Thinking to fool the meter right back, we learn of something that is often touted as fail-safe: the gray card. This helpful aid, when placed in the light that prevails in your scene, gives the meter something to read that is just what it wants to read. So when you ask Mr. Polar Bear to hold it for a minute and hold the gray card up next to his massive head for a reading, it hardly matters that your subject is white-on-white (although it may still matter to you that you are in danger of becoming a bear’s dinner). You’ve overcome the limitations of the meter, and your exposure will be perfect.
You’ll read this endlessly on the internet. Want perfect exposures? Meter off a gray card.
Well, I don’t mean to dismay you so early in the game, but gray card readings can be wrong when it comes to exposing B&W film.
Here’s why. Let’s say you have a film that will record seven stops: middle gray, plus three shades lighter and three shades darker. Now, you come across a scene that has—oh baby—seven stops of luminance. You deploy your gray card, and the camera’s meter gives you a reading (fig. 1). Middle gray in the scene will then be the perfect density on the film to replicate middle gray. The darkest part of the scene is three stops darker, but your film can still record that with detail. The lightest part of the scene is three stops lighter than middle gray, but, fortunately, your film can handle that without blocking up.
And your exposure is perfect. Just as the theory predicts. Pat youself on the back and swell with pride at your knowledge of the gray card.
But now, the next scene you wish to photograph is low contrast, and only has five stops of luminance. You deploy your gray card, take a reading, and make your exposure. You’ve again matched middle gray perfectly, of course. Turns out, though, that the resulting negative is “flat”: that is, what you meant to record as the darkest value in the scene is actually one stop lighter than your film can record, and the lightest value is one stop darker. But no matter. Back in the darkroom, you use a higher-grade paper, and all is put right again. No problems yet.
But you see where this is going. Down the trail, you have come across a dazzling high-contrast scene, which has, let’s say, nine stops of scene luminance. Deploying your gray card, you are assured that middle gray in the scene will be middle gray density in the negative. But here’s the rub: the darkest part of the scene in which you want there to be detail is one stop below your film’s ability to record minimum detail—it is four stops darker than middle gray, whereas your film can only record detail three stops down. Similarly, the lightest highlights in which you want detail is one stop higher than the limit of what your film can record. Problem! Since the old aphorism instructs you to “expose for the shadows,” your gray card reading has caused you to underexpose your negative by one stop. The darkest parts of the scene that you wanted to record with detail are, on your negative, clear, featureless film base. No detail. Unlike the situation with the low-contrast scene, nothing you can do in the darkroom can rectify this. To add insult to injury, your average “normal” development will block up the highest highlights, too. You might be able to fix this with burning, or with a low paper grade, in the darkroom. But nothing can help the fact that you’ve unexposed by a stop.
Your faithful gray card has misled you. It has exposed you to error! Its averaging has been below average! (Hoo, boy.)
Part II: Automation and Interpretation
In Part I, I tried to demonstrate why even a gray card is not always a reliable way to meter. Now you just need to know that "averaging" metering itself is also a form of "gray card."
That is, we start with the presumption that all the various luminances in a scene will sorta average out to middle gray, and then the camera "reads" the scene as if it were middle gray. It suffers from the same limitation as the gray card reading, plus one more: the fact that the luminances in the scene may not average out to be something close to middle gray. What if it's mainly black with a little white, or mainly white with a little black, so-called "low key" and "high key" scenes? We run into problems. This is the very defect that the gray card is intended to fix.
But both these methods essentially tie exposure to one middle value. And, for the reasons I outlined in Part I, that's never perfectly reliable. So what is?
Here's where we come to the old saw, "Expose for the shadows, develop for the highlights." Virtually all precise exposure and development systems tie exposure to the reading of two
values. Instead of reading one value in the middle, we read two values,
one at either end: shadows and highlights. It's true of the old studio
incident system, the Zone System, BTZS, all of 'em. No matter what
system you use, it's imperative to get enough exposure in the darkest
values so you have some detail there. Then you have to develop the
negative so that the highlights aren't too strong or too weak.
The problem with these sorts of systems? Only one, really, which is that they depend on fairly involved and time-consuming metering and materials testing procedures. This makes it tough to use the systems with roll film and 35mm film, and tough to use while working relatively quickly. It’s why large-format photographers are mainly the ones who use these systems.
Here it might be useful to backtrack a bit, and take a look at who came up with today’s conventional exposure and contrast control schemes, and how.
Many photographers, being of a sound, scientific cast of mind, trust measurements. They tend to denigrate “eyeballers,” people who simply look at prints and proceed by guess and by gosh. Remember, though, that photographers had been eyeballing prints for decades by the time Hurter and Driffield came along, in the 1890s, with their “H&D curve,” which plotted exposure time against negative density. Eventually, of course, in the 1930s, Kodak came up with a workable general system of exposure and development control that is still in use today: their solution was to settle on basic average exposure and average development, and then control contrast in the printing stage, by using papers of varying contrast.
But what to shoot for? What’s an ideal print, and what kind of negative best allows you to make it? It might surprise you to learn how they found out…by “eyeballing”! Kodak scientists C.E.K. Mees and Loyd Jones proceeded by making large numbers of prints and asking a statistically significant sampling of viewers to rate them. This oversimplifies the history a bit, but the upshot is this: the end result of all our measuring is to get us to where a bunch of eyeballers told us to go.
Forward to the past
So there are these two approaches to the problem: strict control using involved metering and materials testing, and the “middle of the road” averaging methods that form the basis of so much common practice. In the next part of this article, I’m going to propose what I think is a relatively simple and fast black-and-white exposure and development scheme for roll-film users that falls somewhere in between the extremes. For me, it’s worked out to give me the best success rate of all the various systems, all things considered.
But first, I want to say a few words from a philosophical standpoint about one of the drawbacks of automation.
This gets back to what I said at the beginning of this article which is that when a black-and-white print departs from the average, it becomes an interpretation. To illustrate this, I want you to consider boatbuilding for a moment. In the old days (and, in small numbers, still), boats were built from wood, by hand. Baotbuilders were thus constantly trying out new designs and ideas and, in the process, constantly evolving boat design in a creative and ideophoric fashion. These days, most boats are built of Fiberglas, which involves very expensive molds from which large numbers of boat hulls must be cast. This has some advantages, but one disadvantage is that the progress of creative boat design has slowed down to a crawl.
Well, I’d like to argue that the same thing has been true of the automation of exposure in cameras. By always allowing our cameras to “average” for us, we have forgotten how to interpret artistically. In the bad old days, exposure and development wasn’t easy, but eventually photographers did get a sense for what they had to do to achieve interpretation. I think I could come up with literallly hundreds of examples, but look at the following illustration for just one. Progress isn’t bad, of course, but, as usual, we’ve lost something, I think.
Madness by Gene Smith. An automatic meter
would have made a mess of this. By trying to make the background middle
gray, it would have dramatically overexposed the face. (Another of
Smith's interpretations of this picture puts the man's face lower and
more to the left, and darkens to black most of the background detail.)
Part III: Mike's Private System, Revealed At Last!
Now I have some good news and some bad news. If you've been following along over the past two parts, I hope what I have to say next won't make you cross. However, the sad truth is that making really "perfect" negatives and prints with any consistency is nearly impossible.
Mind you, when I say that, I have a very exalted standard in mind.
Namely, that you understand the technical characteristics of your
materials and how they relate to each other; that you find scenes that
translate particularly well into tones; and that you have given the
film exactly the exposure it wants, and then given the exposure exactly
the development it wants, so that the negative will give the printing
paper what it wants—and, last but not
least, so that the print the printing paper yields will express the
interpretive effect you wanted when you started. It's
all a rather involved business. Despite the assumptions of the
scientists among us, it is not purely a technical matter; recall that
Ansel Adams, for instance, was already a very experienced photographer
when he first devised his Zone System. I'm afraid that no matter how
firm your technical control, some experience and some judgment still
are required. And, for those bold souls among you who pooh-pooh
measurements altogether and proceed by the seat of your aesthetic pants, testing
the wind with a wet finger, I'm sorry to say that striving for perfection does indeed involve a
great deal of repeatable science, in the form of testing and
measurement and (perhaps especially) a strict controlling of variables. Ed Weston notwithstanding.
And even if you do completely master all of this (many have tried, so a few have in fact succeeded), the problem then becomes that you are so preoccupied by it, not to mention occupied by it (because it does take a good deal of fussing and messing about), that you are likely to miss a great many of the good shots.
The big anticlimax
But that's only the bad news. The good news is something you already know: that, with photography, as with horseshoes and hand grenades, close is good enough. The delightful truth is that if perfect negatives and prints were all that worked, photographs would be rare in the world, instead of the world being awash with them. In fact, the photographic process admits of a good deal of abusing. A great deal, in some cases. Ahem.
The solution I came to years ago, which I hereby dub with the
handsome name of Johnston's Not Much of a System System, depends from
the following principle: Firstly, get the picture. That is, it's worth
it to pay attention mainly to what you're shooting and end up with a decent
print of a great shot, as opposed to paying attention to your meters
and measurements and end up with a perfect print of a dreadfully boring
shot of nothing.
And to do this, we really only need to remember the reason why the
gray card doesn’t always work, which is that tying exposure to a middle
value doesn’t always nail the shadows. So, really, all we need to do is
to apply judgment and experience to determine what will. And that's not so hard to do.
Here’s what I do. I pick a forgiving film (in my case, Tri-X 400). I use the in-camera averaging meter. Then I establish a good baseline average exposure and development for normal scene contrast. For my film, in my developer (D-76 1+1), with my development and inversion technique and with my enlarger light source (dichroic-style diffusion), that’s E.I. 200 at about 10% less than the recommended time. When I encounter low scene contrast, I switch to ISO 400 and goose the development 30% (i.e., 30% more than my standard time); and when I encounter high scene contrast, I shoot at E.I. 100 and cut back by another 15% or so. (This is easiest to accomplish when shooting with a camera that has interchangeable backs, of course, but when I’m shooting with one camera I change the ISO dial to match the light and stick with the middle development time.) Finally, I'm prepared to add one stop of exposure compensation for obviously high-key subjects, to avoid underexposure.
Now, I know, that seems scant payoff for all this reading, and I know it sounds anticlimactic. But it might surprise you to know that my Not Much of a System System gives you perhaps 80% of what the Zone System does. Because really, most ZS development is N (normal), N+1 (essentially, my 30% increase), and N-1 (my 15% decrease). To replace the ZS’s fastidious measuring of the shadow values, just judge the character of the light by eye and reset the ISO dial. It’s not quite as precise, but then, it doesn’t really need to be—because we can still use paper contrast grades, after all, and films are much more forgiving than they used to be.
So how would you go about running a trial to see if you’re on the right track? Why, try it, of course. Give it a go and eyeball the results. Adjust to taste. They’re your pictures; make them look as you’d like them to look.
And how do I know I’m on the right track? Ah, I was hoping you'd ask. It's because the nose-in-the-book measurement folks think my system is intolerably imprecise, and the shoot-from-the-hip crowd thinks it’s finicky and involved. That’s how I know. It splits the difference—and offers the best of both worlds, I think.
Part IV: The Old Ring-Around
In Part III, I gave you the details of Johnston's Not Much of a System System. To recap:
• First, settle on a good basic exposure and a "normal" development time for your film.
Whoa. Hold it right there, you could well be saying. Pick a standard exposure and development time? What? How? And what the heck fool kind of exposure and development system starts out by assuming you already know where you want to end up?
There’s no substitute for experience, and the best way to learn how a film behaves is to use it for a long time. But even if you've already done that, it's a sad fact of contemporary life for black-and-white photographers that more and more often these days, we may be forced into changing the film-developer combinations we use because older materials are taken off the market. It’s not the films we lose that are such a tragedy; it’s that by taking away our favorite materials, we lose years of hard-won experience in the time it takes your store's stocks to run out.
There are ways, of course, to get up to speed with a new film quickly and efficiently. When I learned photography back in ye olde 1970s, we were instructed, when faced with a new film and developer combination, to do a simple trial called a “ring-around.” A ring-around is a grid chart of nine photographs, all of the same scene, arranged in three rows of three. Horizontally, the rows are “underexposed, “normally exposed,” and “overexposed,” and the vertical columns are “under-developed,” “normally developed,” and “overdeveloped.” This (obviously) gives visual confirmation of nine different combinations of exposure and development. Photographers in my day were always divided as to whether the prints from the test negatives should be made to a uniform contrast grade and enlarger exposure time, or whether each negative should be printed as well as it could be. I always opted for the latter, reasoning that no matter how your negative is exposed, you’re always going to try to make the best print you can.
Then in 1981 came the landmark publication of the final editions of Ansel Adams’s instruction trilogy, The Camera, The Negative, and The Print. (There was also a book called Polaroid Land Photography, done probably as a favor to Ansel’s friends at Polaroid. Although similarly bound and presented, it was never an essential part of the set, and is of course even less relevant now.)
Of the three, the most crucial was The Negative. In it, Adams included an Appendix entitled “Film Testing Procedures,” describing how to pre-determine exposure and development sensitometrically.
Adams’s procedure was rigorous and scientific. The ring-around was roundly decried as simple-minded and anachronistic, and it fell out of popular favor. I was a stranger neither to fashion nor to a certain snobbish superiority, so I embraced the new methods wholeheartedly at the time, and did my share of scorning the old.
Many of you use the Adams testing procedures, and of course make them work well. But as the years have passed, my allegiance has slowly shifted back to the old ring-around (fig. 4) for testing new film-developer combinations. There are two reasons why. First, in the interim I’ve seen an awful lot of work done by “Zone System” photographers, and some of it, done in slavish adherence to Adams’s negative density numbers, looks quite wrong to me. Adams had a particular style that almost everyone admires, but that doesn’t mean it’s the right style for everybody—and, especially, it’s not for people whose judgment isn’t well-honed. My father always used to say, “If it works, you’re right, and if it doesn’t work, you’re wrong.” Appealing though Adams’s scientific approach may be, the bloom sometimes comes off the rose in practice. It simply doesn’t work very well for everybody.
The second reason harks back to the simple but hardy advantage of the ring-around: it gives you its information in visual form. Even if you already know your exposure and development preferences (I prefer over-exposure and under-development, for instance), it imparts to you a seat-of-the-pants feel for how each specific film behaves that can come in very handy.
The biggest problem with the old ring-around test is that it’s a lot of work to carry out. You have to expose three films, and of course you can’t develop them together. (Quiz: what's your best clue that the above illustration is a digital forgery?) And the nine prints are just a pain to make, deprived as you are of the motive of artistic inspiration. Even as a teacher, with the weight of authority behind me, I was never able to coerce even high school students to make a ring-around more than once. If that.
But if you can stand the work, a ring-around is about the best method to come up to speed with a new film and a particular developer. To make a ring-around, the classic recommendations are to follow the camera’s averaging meter for the “normal” exposure and then to under- and over-expose by one stop. For development, the recommendation is 20% under and over. As I say, in making the prints I simply try for the best print I can make from every negative. Of course, you can modify any of these recommendations to your own taste.
The ring-around is most informative and most efficient if you do two of them—one of a bright, high-contrast scene such as a sunlit landscape, and one of a low-light, low-contrast subject such as an indoor available-light portrait or still life. And, naturally, though it sounds very grade-school to do so, it’s nicest if you mount all the prints in a grid on a large posterboard.
And remember, there’s no particular magic in any particular film, regardless of how well you knew it and how much you liked it; with skill and judgment—and perhaps a good old ring-around—you can do as well with another. So if you lose a favorite, take heart.
Back to the recap
So then—now we can get back to the recap of Johnston's Not Much of a System System. Because really—I'm being honest with you here—you don't actually have to do a ring-around for yourself. You can take my word for it: the JNMSS takes into account what you'd learn from doing all that work for yourself.
• First, settle on a good basic exposure and a "normal" development time for your film. (Half the manufacturer's recommended ISO setting and 15% below its recommended normal development time for normally-exposed negatives will usually serve as a good approximation of this.) Use this for normal shooting.
• When shooting low-contrast scenes, especially in low light, set the ISO dial for one stop less exposure, and add 30% to your normal developing time.
• When shooting high-contrast scenes, especially in strong light, set the ISO dial for one stop more exposure, and develop for 15% less than your standard time.
• Don't worry about metering "low-key" scenes (mostly dark or black values) differently—just pay attention to the constrast of the light. Shooting a low-key scene with your normal metering will still result in getting all the information you need on the negative to make a good print.
• With "high-key" (mostly light or white) scenes, add an extra stop to the camera's metering, over and above what you've already done to compensate for the contrast of the light.
• If you're shooting rolls of film under varying kinds of light and scene contrast, just stick to your established normal development time, and just vary the ISO on the dial to compensate for the type of light you're shooting under. Your negs won't be quite as easy to print this way, but you'll be okay.
So—not much of a system, eh? Told you. But what it lacks in elegance, it makes up for in practicality. It's easy to apply, and it lets you pay the most attention to what you're shooting, rather than getting distracted by metering and plans for how you're going to proceed in the darkroom.
Originally published in Black & White Photography magazine
Copyright 2004, 2007 by Michael C. Johnston—All Rights Reserved
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