You probably remember Part I, from a week ago Saturday. You might want to go back and re-read that before diving into this part. First, to reiterate: no B&W film photographer needs to practice sensitometry. It's absolutely not necessary for doing good work. This article does, however, contain information of real value for all APUG-type B&W photographers, so don't skip it if you're one of those—even if you have no intention whatsoever of buying a densitometer or practicing sensitometry.
As an aside, since a week ago Saturday I have acquired not one but two densitometers...
The second is a very nifty secondhand Heiland TRD2 which is a transmission and reflectance densitometer in one, meaning it reads both negatives and prints. It was offered to me by TOP reader Jeff S. for a good price after I had already "won," on eBay, a very nice Eseco Speedmaster TRC-60D, after various web researches turned up a number of recommendations for it from photographers doing what I wanted to do. I was amazed when I got the Heiland—for someone who has only used big, heavy Macbeths in various workplaces, the box seemed too small and altogether too light to contain a densitometer. The Heiland turns out to be a wee little thing.
Eseco is still very much in business in Oklahoma, and still includes densitometers in its product offerings even though there's very little call for them—the current model is the battery-powered SM-10T. When I asked if the TRC-60 could still be serviced, the answer was "almost"(!). Last made in 1985, the parts for it are now mostly gone, but the Service Manager told me that Eseco still has people around who know it well enough to get most any broken one working again. On the good side, he said working ones will most likely keep on working, with no need for service. (Densitometers are apparently very robust devices, that typically keep on going just fine for years and years.)
The all-important FDP
So here are a few reasons you might need a densitometer, in descending order of importance: If you review B&W films and papers for a living; if you use lots of different materials and you like to get up to speed quickly and efficiently; if you're looking for an optimal FDP combination (more on what that means below); or if you just think that sort of thing is fun. (Maybe that last reason should go first.) Another reason is if it helps you to work at the limits of control, although—I'll say it yet again—you don't need sensitometry to do high-quality work in B&W.
One thing it does help with, indisputably, is understanding FDP combinations, and this is where Phil Davis (author of Beyond the Zone System
—which, as one Amazon reviewer points out, could have been called "Sensitometry for Photographers") comes into this picture. There are three things that determine the look, or the tonal signature, of traditional B&W materials—the film (F), the film developer (D), and the paper (P)—"FDP." This is important: there are lots of people (one might even say "all people" within loose tolerances) who "test" B&W materials using what I'd call the "fake experimental method." That is, they tightly control all of the variables and change only one, then draw their conclusions from the differences they observe, assigning those differences to that one cause. The problem is that all three variables influence the final result.
That is, if you use film A, developer B, and Paper C, you can't just switch out developer B for developer D and reach any meaningful conclusions about either one—because you're only testing them with film A and paper C, and your conclusions are only valid for those variables. This doesn't stop people from generalizing madly based on their supposedly "rigorous" trials. Phil was quite contemptuous of this—if you changed one of the three variables and drew conclusion x from it, he could suggest changes to the other two variables that might change your conclusion to y and not x. Add to this the variations within each variable—how much development a film received, different developer dilutions, which paper grade you use—and you have a tarpit that no one gets out of alive.
Phil's belief was that measurement was the only thing that could save us from the tarpit. He once said to me that with his measurements he could learn in an afternoon as much as an "eyeballer" could learn in the darkroom in a year. (Eyeballer was his grudgingly affectionate term of disapprobation for reprobates like me who flew without instruments.)
Phil's Plotter program
I just had a great conversation with my old friend Fred Newman of the View Camera Store, who must be close to the friendliest guy on god's green earth—or should I say, god's arid, sun-drenched, sand-colored earth, since he's down in Scottsdale, Arizona. The current version of the old Plotter/Matcher program, now called Plotter for Windows, which was ported to Windows by David Jade and has been improved since Phil's death by Fred and David, will run on Macs under an emulator, so he's going to send me a copy—and I'll review it, if I can, in due course. So I'm going to make this rather brief, to just give you a general idea of it.
To show you how it works, more or less, I first pulled out of mothballs my old Macintosh Powerbook 180, which is the only computer I have that Phil's old Plotter/Matcher will run on. (This computer sure was a lot more handsome when it was new!) The old machine is balky, and the trackball needs a good cleaning, so I was barely able to make it work.
To begin with, here's a typical "family" of film curves—this is Ilford 400 Delta sheet film, developed in straight ID-11 (Ilford's version of Kodak D-76). The test films were developed in BTZS Tubes for four, five and a half, eight, 11, and 16 minutes. You can see how the high values get more dense with more development (that's log density on the y axis) and how the contrast goes up—that's shown by the basic slope of the curve. You can also see that the speed point (.01 above fb+f, or the point where exposure begins to register) moves to the left slightly with increased development—yep, film actually gets "faster" (slightly) with more development.
So that's F (film) and D (developer). Different developers might change any of this data even for the same film: the speed point, the contrast with any given development time, even, in some cases, the shape of the curve.
(I can't resist an aside to those who are participating in what appears to be a fad on flickr for extremely dilute Rodinal: Rodinal in high dilutions frequently develops to completion/exhaustion, meaning, the curve stops changing after a certain amount of development time has been reached—so it's possible that you're developing for an hour and not making any difference at all over developing for, say, fifteen minutes*. You'd have to test to be sure. Suffice to say that there's a pretty high likihood that with extremely long developing times in extremely dilute Rodinal, not only is no magic happening, but nothing may be happening at all. On the good side—sort of—that's also why "stand development" with Rodinal doesn't result in streaky, blotchy negs—because if nothing's happening, nothing bad can happen.)
Now here's a family of paper curves. This is Agfa Multicontrast Classic, one of my favorite papers, which has recently been revived (on a whiter base) under the name Adox Premium MCC**. To begin with, remember that this is paper, which is the inverse of the negative—so this curve is "upside down"—the less dense highlights are now at the bottom and the denser dark areas at the top.
And here's where most any B&W printer can learn a few things. Do you see how weird and lumpy the lowest-contrast curve (labeled "2") is? That's the reason you should never target your negatives to a low contrast grade on VC papers—shoot for at least grade 2 or even 2.5 or 3 to get into the middle of the paper's comfort zone. Also, ignoring the outliers—1 (all the way to the left) and 7 and 8—do you notice something else funny about the remaining curves? Note how the curves don't really begin to diverge from each other until about 1.0 density. That's when the different grades start to split apart. What that tells you is that with this paper, highlight contrast doesn't really change much with changes in filtration—and that turns out to be true for most VC papers. That tells you two things—first, you need to match your film to a paper based on the way you want your higher values to look, and second, when you expose under the enlarger, you do just the opposite of what you do with film—expose for the highlights and then adjust contrast with contrast filters. So when you make a test strip with VC paper, evaluate the highlights, disregard the shadows.
But to continue. Here's the payoff, and what the "matcher" part of Phil's Plotter program does. There are a couple of intermediate steps (mainly, you have to pick one particular film curve and one particular paper grade), but the Plotter basically matches the film's curve (in, you'll recall, the developer you chose) to the paper's curve, and gives you the charactersitics of the FDP***. Phil also devised a way to give users a quick visual read on what's going on—the two bar charts on the right-hand side.
This chart happens to represent my own standard materials at the time—35mm Tri-X 400 in D-76 1+1 for 8.5 minutes, plotted against Agfa MCC in Neutol WA 1+7. The bars show the tones from both ends expanding into the middle—the dark zones raised in value considerably, and the highlight tones taking up a bit more of the scale. And that is indeed how they printed—giving just the look I happen to most like.
A year's work in a day
Traditional B&W photographers who printed their own work spent a great deal of time and effort struggling to correct for the inherent characteristics of their materials—"fighting" the materials, as Phil used to say. Much of the darkroom heroics you read about all over the literature were simply the result of the photographer wanting a different look than the materials, combined, wanted to yield. Contrary to (very) popular belief, "trying lots of different materials for yourself" was really no better than stumbling around in the dark to see what you might bump into. When you got the FDP combination that matched the look you wanted, as often as not the negative would "fall on to the paper," as printers sometimes put it. Printing became easy. Well, easier, let's say. Darkroom workers had nothing but experience and long familiarity with their favorite materials to guide them, and that was indeed serviceable knowledge. But even then they were basically lost when it came to replacing old materials they liked with a new substitute, when, for instance, an old film or developer or paper was discontinued—and that's been happening regularly since optical/chemical photography was young, not just recently.
Phil Davis's idea was to spare people all that, and just let them find quickly the materials that suited their tastes. Once you knew how you wanted that bar chart to look—approximately where you wanted those "reference grays" to go on the "print grays" bar—finding different materials that yielded the look you liked was just a matter of poking around in the data until you found what you wanted. If you changed one variable, you could see exactly what effect it had on the tones—and, if you wanted to, you could change something different to change it back again. Each change of variable represented how much time in the darkroom—a hundred prints? At least a dozen. Phil was really right—as long as you had a large enough database of materials tested, you could gain the knowledge of a year's work in a day.
• • •
And in closing, may I just say how much I miss Phil, who died in 2007. (There's a picture of Phil and me here.) For more than six years we exchanged emails, often long ones, daily, sometimes more than one. We were not in contact much in the year or year and a half before his death—he was unsentimental about his own demise, and found my solicitous concern for his health after he got cancer tiresome—but for many years he was a good friend and faithful correspondent, as well as a wise and always challenging teacher. On the phone today, Fred mentioned that Phil had forgotten more about B&W technique than most photographers ever know. Truer words were seldom spoken.
Mike
*Don't think I'm so smart—I learned this lesson the hard way. When I first tried extended development in dilute Rodinal—1:100 or 1:150 for 45 minutes or an hour, I think it was—I mentioned in an email to Phil that I'd gotten very pretty negatives but that I'd nearly driven myself out of my gourd with boredom. "Anyway, it works," I concluded. About half a day later Phil emailed me back and told me to try the exact same technique, but for 18 minutes or whatever it was. I did, and the negatives were...to my amazement, essentially identical with the first ones. He had run some quick tests in the intervening time and determined what I conveyed to you above.
**Agfa Neutol WA, which was my choice for the best paper developer for Agfa MCC, has also been revived, under the name Compard Print WA.
***Some readers will have realized by now that when you scan negatives, you're not quite seeing the way that film and that developer were intended to look, because the manufacturer designed the material to be matched subsequently to a printing paper. When scanning, you don't get the paper curve's influence on the result. You can also apply other curves at will in Photoshop or any other image editor that has a curves function.
, in its various iterations over the years possibly the most inspirational technical book ever written (cited as such by literally generations of photographers):