I've been asked many times over the years to write a post about B&W tonality, and I guess it's time. It's a big subject.
I'll be writing this entirely from an aesthetic perspective—I'm not an expert in the many ways to do B&W conversions, and I don't care how you do it. What I'm interested in is what we end up with (the "why"), not how we got there (the "how").
To begin with, a few basic notions about contrast. You've probably heard it said that the best print (or file—again, don't really care how you're looking at something, just what you're seeing—) is one which "has a pure black and a pure white."
Here's a nice scenic picture with a pure black and a pure white:
...So that isn't terribly helpful.
Some people then amend the recommendation to say "a pure black and a pure white with a full range of tones in between." Let's have a look:
There, that seems better. Job done?
As an aside, don't think that the first strategy—high contrast—is necessarily invalid. Take a look at Daido Moriyama's famous "Stray Dog" or Bill Brandt's "London (Nude with Bent Elbow)":
Unabashed masterpieces of postmodernist and modernist photography respectively. Both with very little in the way of middle values and high contrast, although Brandt's picture at least is often printed with some tone in the whites, and the small details of middle values are absolutely crucial to the picture.
...But to continue. You might think that the "full tonal range" scene in Figure 2 answers the edict—but within that full range of tones between pure black and pure white, how do you want the tones arranged? Let's use some examples:
Figure 3 might look "darker" or "higher contrast" than Figure 2, but it isn't. It shows the exact same extremes and the same range of tones as Figure 2. But it looks quite a bit different. Now let's look at another interpretation, also with the exact same extremes and the same range of tones as both Figure 2 and Figure 3:
You might suspect that these are "filter" (virtual color filter) adjustments, but they're not. All that's happened here are two simple curve adjustments. In Figure 3, all the values are depressed—middle values most of all—pushed a little darker than they were in Figure 2. In Zone System terms, zone V is pushed to zone IV, and all the other zones are lowered in value to a lesser but proportional degree. In Figure 4, the opposite has happened—the tones have all been raised to somewhat higher values, middle values most of all—zone V is now zone VI. (This is what would be called "open contrast.") But Figures 2–4 all show "pure black to pure white with a full range of tones in between."
The best way I've encountered to chart visually what's happening here was with the late Phil Davis's Plotter/Matcher. Phil's idea was that, using a densitometer and step tablets, each hobbyist/photographer would plot a whole family of film and paper response curves. The Matcher would automatically match up any given film curve with a specific paper curve—allowing you to see by measurement, rather than by eye, the tonality inherent in any given combination. Alas, despite my importunings, Phil wanted everyone to become an amateur sensitometrist and build his or her own library of curves. (I wanted him to sell the Plotter/Matcher program with a full set of data, but he considered that this would have been "cheating" on the part of the purchaser. Did I mention Phil was a University professor?) This was rigorous, but less than practical. He had few takers.
However, in my privileged position as the Editor of the magazine that published his work, he let me have his full set of data. The visual shorthand in the program was a bar graph divided into seven or nine incremental grays. Against a theoretically neutral graph of gray zones, another alongside it would show what the film/developer combination would do to the tones—shift them all down or up, "bunch" them at the top or bottom (low highlight or shadow contrast), contract some and expand others, or what have you. It allowed you to see at a glance what the tonal properties of any given film/developer/paper (FDP) would be.
Phil's idea was that instead of "fighting" any given set of materials to get the look that was wanted—the film photography craftsman's traditional solution—you could just pick the materials that gave you exactly the look you were after, and let the proper tonality "fall on to the paper." Or, you could go the other way—learn what the properties of your materials were, then just accept that and stop fighting it.
We'll revisit these ideas later, because digital very much likes one particular kind of tonality at the expense of many others, and the number of people who don't understand it is exceeded only by the number of people who can't even see it. Or rather don't see what they're looking at.
The next problem with the old adages dictating "from pure black to pure white" or variations on that theme is that it puts us into a needless box, a bind, and deprives us of the delights of using only parts of the tonal range in pictures. Why would anyone want to do that?
Traditionally, pictures that use only light tones are called "high key," and pictures that use only dark tones are called "low key." Among the most amazing examples of low-key work I've ever seen are some of the pictures in John Gossage's Berlin Wall work, which were virtuoso performances both of seeing and using (and rendering) tone. John was very daring in using only the darkest tones in some pictures, in some cases right on the edge of intelligibility, and only the merest traces of highlight accents in others. I can't find it online, but one example shows the hulking outline of a huge building, solid black, against a night sky that was only very slightly lighter than black—tones so close it was almost difficult to see.
A (very) low key photo by John Gossage from
Berlin in the Time of the Wall, via odaaniepce. Thanks to Gene D.
So much for pure black to pure white.
Really, though, there's no reason why "middle key" B&W photographs shouldn't be included too—pictures made up of only middle grays—fog or mist scenes, to name just one example. In fact you can use any given part of the tonal scale for a photograph, with or without small accents outside that range.
Johnston's first rule
Takeaway for now: every time you hear a rule for the way B&W is "supposed" to look—the pure black and pure white thing, the "full range of tones" idea, placing human skin on zone VI, et cetera...whatever it is, ignore it. Johnston's First Rule of B&W Tone is that there are no general rules that always hold true—and many such rules don't even address some of the important issues. That doesn't mean anything will work, or that results don't matter—far from it in most cases—just that oversimplified adages aren't typically very helpful.
That's enough for today, but this just scratches the surface of working with tonality. There's a lot more to cover. Next time, subject brightness ranges, or, how to cram a lot into a little.
P.S. It's going to be unavoidable that the illustrations don't look quite right. I've tried to exaggerate them so they'll be comprehensible as illustrations, allowing you to quickly get an idea of what I'm talking about, but making them tiny and then loading them into the blog software destroys a lot of subtlety—in particular, it's hard to see any "white" highlights in Fig. 2. I've long let this stop me from writing posts like this; I think it's worthwhile to try to forge ahead anyway, even though the illustrations are only approximate. Please take them with the appropriate dosages of salt.
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(To see all the comments, click on the "Comments" link below.)
Featured Comments from:
David Cope: "Looking forward to this series Mike. It's a subject area that underscores that B&W is such an exciting medium to work in. I know this is the how, but I've been experimenting with high key by letting the CCD in my Olympus E-1 overload somewhat and seeing what it produces.
"If I may, this picture provides the why. This is a shot of spring blossoms where shooting backlit into the sunlight has produced an almost hand-drawn ink-on-paper look. Only a bit of burning on the left flower was needed to pull tones towards black; otherwise it was white with upper mid tones. Practically monochrome TIFF straight out of camera."
Mike replies: Beautiful.
Stan B.: "The thing I have a problem with is 'the difference' in tonal values between digital and analog B&W. Sometimes, they really do look like two different animals. Digital B&W in open shade can look absolutely phenomenal, in sunlight...it can really vary. I think often it's simply because a lot of people are just too damn lazy to do it right, some just setting it to a preset and washing their hands of it. Sometimes, I can post process color in a matter of minutes, B&W can take me days. When you have 'less' to work with, you really owe it to yourself (and the medium) to do it right. Although I sure as hell can't prove it technically, I suspect that digital somehow, some way is susceptible to coming up short in intermediate tonal values, particularly in direct sunlight (kinda like compressed audio files)- not to mention you can't retrieve tonal values in overexposed areas to the extent one can with film. And I really hate it when you have scenics, or even street shots, filled with featureless, washed out skies or other areas devoid of any tonal value."
Mike replies: There are two reasons for what you may be responding to. One is that digital has inherently low highlight contrast and excellent shadow contrast, and most B&W films get it the other way around—they have inherently low shadow contrast and excellent highlight contrast. Unfortunately, the way human beings see matches the way film sees—we're very good at discriminating small differences of tone in highlights and poor at discriminating tonal differences in the near-dark (hey, it's part of being diurnal animals). There's more to discuss, but I'll be getting to this later.
tex andrews: "I'll vouch for the Gossage work...pretty amazing. He was teaching at the University of Maryland when I was there in grad school. Sadly I didn't work with him; wish I had. he didn't stay long...the department really didn't know what to do with him."
Will Hoffman: "I was taught to shoot for print reproduction. Newsprint "blocks up" over about 93% so my instinct is to not push the blacks. Digital is almost opposite. People looking at screens tend to respond to rich blacks it's taken me a while to allow some blacks to go textureless."
David Babsky: "Adrian Ensor was—and is—the 'go to' man for printing in London...he brought out the full range of what was on the negative for many a famous photographer. And yet his own photos, nowadays, are very, very dark. (Though that's not his personality: he's bright and impish!) I can't understand it: for everyone else's photos he made 'sparkling' prints: for his own, he tends to make almost impenetrable blacks, with very little relief (...though his 'Gallery' pages on his website do have a fair bit of grey, but the overall impression—for me—is of doom and gloom!)"