As long as I'm retelling old stories, and since Howard Cornelsen brought it up in the comments to the previous post—and while there's still a bit of rosy afterglow to the "Fun with Medium Format" post left in the Western sky—I thought I might share again an account of some historical investigations into format and enlargement sizes, one an experiment done by a friend and one done by me.
Every photo writer, and most every serious photographer, has at one time or another exhaustively tested one or another aspect of photography. Real, comprehensive experiments, I mean, rather than the usual gambit of doing some reading, collecting some anecdotes, putting a wet finger to the wind of popular consensus, and adding enough personal trials to simulate comfort. None of us can test everything ourselves, however, so we rely on each other. I first realized this when I read a now-very-old article by George Post in Darkroom Photography magazine (which I later wrote for myself) called "Shake It Up!" The article was about agitating film. At the time, I was big into doing my own experiments and seeing for myself, but after reading George's article, I realized, in one of those little epiphanies we all have every so often (in cartoons, the light bulb lighting up above the character's head), that George had done more work investigating agitation methods than I would ever duplicate if I had nine lifetimes, and that I would be better off "evaluating the evaluator" and accepting their conclusions if I thought they were trustworthy. I adapted George's conclusions to my own needs, and never looked back. I remain grateful to all such investigators, from Richard J. Henry to Ansel Adams to Ctein, from all of whom I learned much.
Two tales told by actual prints
The first of these two tests was carried out by my friend Jim Sherwood, with whom I've lost touch. Jim's work at the time (he photographed dense, busy, chaotic scenes, often of the aftermath of natural disasters) was made with color negative film in a Pentax 6x7, and he made 16x20-inch Type C prints. That's the same basic process drugstores used to make 3R and 4x6" prints from snapshot cameras, except that Jim used a $10,000 Hope processor and made his prints himself. His question was simply whether he might be able to get away with using 35mm instead of 6x7. He conducted these tests sometime around the beginning of the 1990s.
What he did was to optimize his 35mm technique, remain casual with his 6x7 technique, and compare the two. For the 35mm, he used the best camera and lens he could find—his Leica; the slowest, sharpest, most saturated color negative film he could find at the time; and he used a tripod. For the 6x7 he used VPS, a 100-speed (i.e., medium speed at the time) color negative film of good color and what we now call "dynamic range" but only so-so sharpness and saturation, and he hand-held the 6x7 SLR camera.
What he found was...
...that the 35mm matched or bettered the 6x7 in enlargements up to 8x10, 6x7 blew away 35mm at 16x20, and, at 11x14, although he tended to prefer the 6x7, it could more or less go either way—it depended on the subject matter and the specific pictures as to which he preferred. But, generally, as the size increased from 8x10 the 6x7 enlargements pulled ahead. (He stuck with 6x7 for his work.)
For my experiment, I compared 6x7 to 4x5. I made the same landscape and studio portrait using both a Mamiya RZ67 with a 110mm ƒ/2.8 lens and a view camera, a Wista with a Rodenstock 210mm ƒ/5.6 Sironar-N lens, on Ilford XP2 chromogenic black-and-white film, and made comparative prints of various sizes. Because I was writing up the results for Camera & Darkroom magazine, I showed the prints to a sizable sample of actual viewers, both photographers and other visual professionals and "civilians" (ordinary people).
At 8x10, no preference was detectable. At 16x20, the great majority of the photographers and maybe half the others preferred, or at least could recognize, the print from the larger negative. But, significantly, even the photographers couldn't see much difference at 11x14, until I told them what they were looking for (I usually showed them these prints first). Then they knew how to detect which print came from the larger negative. But it wasn't easy—some couldn't guess right even on close study. Among the "civilians," pretty much nobody even cared to voice a preference.
My conclusion at the time? I ended up shooting 6x6 and 645 Tri-X 400 and XP-2 and making 11x14 prints. (I didn't stick with that technique for long; I like grain, and have always loved the look and style of 35mm enlargements. I eventually returned to 35mm Tri-X.)
As I hope is obvious, these conclusions and others like them are indicative rather than substantiating. Each individual's conclusions would naturally vary with his or her technique, equipment, visual standards, and goals—as well as corollary considerations such as materials costs and convenience aspects (for instance, for me it was a high priority to avoid being tied to a tripod) as well as the characteristic "look" of various lens-focal-length to format-size matchups. The experiments have to be set up to answer fairly specific questions that themselves can vary. But, in general, the progression might be graphed as a sequence of fuzzy-ended, overlapping bars, with successively larger formats pulling away from smaller ones as print sizes got bigger—and smaller formats, for the most part, being just as good as larger ones below certain sizes.
And a lot depends on taste, too. Some people really like contact prints, which we did not test—I think my friend Oren would definitely prefer 8x10 contacts to 2X enlargements from 4x5. Personally, I go the other way—I like a little grain in B&W prints, and, to get the degree of grain I liked best in a print, I have to enlarge 6x6 Tri-X 400 up to 16x20—my problem being that I simply don't care for prints that large! I have no use for them, and they take up too much space and money for materials, and require too much effort to make. Eleven-by-fourteen paper is my comfort zone. (Thirteen by nineteen in digital.) Some people also don't seem to mind large enlargements from very small negatives, but I've virtually never seen a 16x20 from a 35mm negative that holds up more than adequately for me, regardless of film, technique, or photographer.
Personally, I'll make 35mm prints up to an "extreme" (not very extreme for some folks) of 12 inches in the long dimension—that's eight diameters—and I like medium format from there up to 16x20, and I leave large format to those who are better at it than I am.
Don't think this isn't an issue in digital printmaking too. Some of the technical issues are distinctly different, printing skill is if anything more of a variable, and there's even less consensus as to what characteristics are desirable. However, I've now used five of the top full-frame DSLRs, from 12 to 24 MP, and my opinion is that format size is even less important with digital than it was with film—and more tied to print size exclusively. (And I've also had it demonstrated powerfully to me—by Paul Butzi, a master printer—that image content is even more of a variable with digital than it was with film. For instance, large areas of bokeh (blur) print fine at very large sizes in digital.)
I would love to do some actual print-size tests comparing my old 6-MP APS-C 7D to the 24-MP full-frame Sony A850 I'm using right now. It would be very interesting, I think, to have the tale of those prints told.
Interestingly, too, there's nothing "soft" or trivial about this method—of showing sample prints to large numbers of viewers and noting their preferences. This is not well known, but it's actually right at the heart of photographic science. It's how the measurable standards we take for granted today were arrived at in the 1930s and '40s, by Loyd [sic] Jones and the great C. E. K. Mees at Kodak Research Laboratories.
The 'sweet spot'
I should add a conclusion here—which is that 6x6 and 6x7 really is a "sweet spot" as far as film is concerned. It's a compromise, but a very effective one. It looks sufficiently different from common techniques to have a certain exclusivity; it can be physically beautiful without requiring fanatical technique; and yet it retains a fair amount of the convenience and flexibility of smaller formats. It holds a decisive edge over 35mm and yet is virtually indistinguishable from 4x5 until enlargement sizes get genuinely big.