[An article about "wrong facts" that was originally published on Photo.net and elsewhere in 2008. This was also where I put forth the argument that 4/3 and APS-C sensors are more alike than different, which did not exactly convince anyone at the time, although I think the world has, on its own, slowly come around to something resembling my point of view since then. —MJ]
Ah, epistemology. The study of knowledge—what we know and how we know it—can always be counted on to be fascinating. Especially, I think, when it’s out there on the dance floor with psychology, doing the foxtrot.
One thing I’ve been aware of for a long time now is that certain bits of knowledge just “seem reasonable” to the human brain. In some cases, these bits of knowledge might be true. But sometimes they’re just completely wrong. And most people go right on believing them anyway.
In photography, there is a whole class of assumptions that fall into this category. They’re just not true, but they seem reasonable to people.
An early example I encountered was a claim by a man named Fred Picker, who owned and ran a darkroom products company in Newfane, Vermont, for a number of years (Mr. Picker died a few years back, and his company, Zone VI, got sold to Calumet a few years prior to that.) Picker wrote that fixer is heavier than water, therefore fixer sinks to the bottom of a print washer, therefore print washers that drain from the bottom are best.
Sounds perfectly reasonable. People believed it. In fact, people believed it so strongly that it became an article of faith…despite the fact that it’s wrong.
Fixer is heavier than water, all right, but fixer being washed out of a print goes into solution with the water and doesn’t separate back out again. Especially in the turbulence of a typical print washer, this happens nearly instantly. And irreversibly. If you take a pint of water and a pint of fixer, mix them together, put them in a bottle, stand the bottle on an out-of-the-way shelf, and come back again after six months, do you have water on the top and fixer on the bottom? No*. Fixer doesn’t separate out of solution with water and “sink to the bottom” of a quiescent bottle over the course of six months, and it certainly doesn’t do so over the course of an hour or two in a turbulent print washer.
In fact, almost all of the fixer carried over by a fiber-based print into the wash is rinsed away in the first few moments. Only minuscule amounts remain, mostly trapped in the fibers of the paper. It turns out that letting a print sit perfectly still in a water bath will usefully leach fixer out of the print and into the water. David Vestal demonstrated that you can wash a fiber print perfectly well in only a few milliliters of water simply by letting the print soak in successive water baths. Try it yourself: with a fiber print fresh out of the fixer, rinse it for a minute or two. Then put it in a tray barely covered by distilled water for ten minutes. Agitate a bit at the end of the ten minutes, drain the water, and repeat the process twice more. Then test the print for residual fixer. You’ll find you’ve gotten a very good wash.
Still, that old idea—that fixer “sinks to the bottom”—persists to this day. I can’t tell you how much time and energy I’ve expended trying to disabuse people of the notion over the years. And when you finally think you’ve settled the matter once and for all, you’ll find that people go right on believing it anyway. Why? Because it seems reasonable—and that’s that. One guy actually told me that he understood and appreciated my arguments, but that he had “heard” so many times from so many sources that fixer sinks to the bottom of his print washer that he was simply unwilling to disbelieve it!
There are several dozen of these persistent myths in photography. The same thing is happening with the newer field of digital—seemingly-reasonable misapprehensions that people can’t be talked out of. One of the ones that annoys me is that 4/3 sensors are “too small.” There’s a vocal minority online who are utterly convinced that the comparative size of APS-C and 4/3 are very far apart and that 4/3 is at a crippling disadvantage in comparison, always, no matter what. Heck, the focal length factors are 1.5X and 2X, and that’s a big difference. It’s true that, as a rough rule of thumb, 4/3 does cost you some fraction of a stop in high-ISO noise. But so what? There are lots of things that determine the speeds at which you can shoot. In fact, 4/3 and APS-C are very close in size. People can’t tell which is which from looking at prints, except when the prints are pushed to extremes and the viewers are told what they’re looking at and know what telltales to look for. And of course many people defend digicams, the sensors of which generally really are much smaller, as being very usable under many conditions and very high quality if used within their limitations. If you think of 4/3 and APS-C as being functionally the same, or at least lump them together in the same general category, you’ll be closer to right than all the people who wail about how small 4/3 is. It just seems so reasonable to them…they must be right.
That’s just one. I could list more, and discuss each one in turn. But it wouldn’t really do any good in the long run, of course.
I have a SaltHill Archival Print Washer—a beautiful thing crafted of smoked Lexan, long unavailable now and rare on the used market. For current products, I’d recommend Robin Whetton’s Nova washers if you live in England [the same company is now called The Imaging Warehouse —MJ] or John Bicht’s Versalab washers if you’re in the USA. The Versalab units are the opposite of the SaltHills in that they’re plain and utilitarian, but alike in that they are expertly engineered and work well.
There are still a few Zone VI products in the Calumet Photographic catalog [...in 2008. —MJ]. One is a circulating washing tray called “The Zone VI Studios Washing Machine.” Sure enough, the description touts the fact that water enters from the top and drains from the bottom—although the bit about fixer sinking because it’s heavier than water, mercifully, is gone now.
* Ever the experimentalist, Phil Davis actually tested this. He mixed working-strength fixer and water 50/50 in a liter bottle, let the bottle sit for an entire year, then carefully removed samples from the top and the bottom of the bottle using pipettes. The samples were identical. No fixer had "sunk to the bottom."
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(To see all the comments, click on the "Comments" link below.)
Featured Comments from:
Remi: "Paul Krugman (who you may or may not agree with) calls those 'zombie ideas': 'a classic zombie—an idea that should have died long ago in the face of evidence that undermines its basic premise, but somehow just keeps shambling along.'"
Mike notes: Below, John's comment answers Peter's question, and Ctein's link explains why.
Peter Wright: "I haven't washed a print in the last thirty years, but I washed a tank of films yesterday. (As usual—ten minutes under running water.) I wonder if the same ideas you write about might also apply to film washing: does a quick rinse followed by two or three sessions standing in still water remove all the fixer residue? In these water-scarce times that would be good to know."
John Ironside: "Having learned the hard way about negative reticulation due to changing wash temperature, I read (in AP/BJP?) of an expert's experiments with film washing by multiple short rinses in still water. I can't now remember the detail, but it was based on measurements of the diffusion rate of fixer leeching out of the emulsion. I think it might have recommended five rinses of three minutes to get an archival concentration. So I pre-mixed a large bucket-full of clean tap water at room temperature before developing. At each interval, emptying the developing tank and refilling it from the bucket. That method was successful for many years until I gave up darkroom work altogether. Earliest negs still look OK after 40+ years."
Ctein adds: Dear Mike, Same here, from the other direction. With pix, even!
Sal Santamaura: For anyone who seeks high quality film and print washers today, I enthusiastically recommend those made by Alistair Inglis."
JK: "I should have guessed that TOP had already tackled the APS-C vs. Micro 4/3 shibboleth. APS-C sensor sizes range from 15.7mm image height to 13.8mm. Image height of an M4/3 sensor is...13mm. It takes some pretty magical thinking to imagine that a millimeter or two should make the slightest difference in image quality. All you really lose is a bit of sensor area to either side. So here it is in simple terms: M4/3 is basically the 4:3 version of APS-C."
Stan Rogers: "About that 'magical thinking'...that mere 2.7mm height difference (compared to the Nikon/Pentax/Sony/Fuji format) amounts to just over 45% more sensor area at a 4:3 aspect ratio, and 84.5% more sensor area at 3:2. Almost half again as much area for the same image is not negligible, not does it require anything like 'magical thinking' to believe that it can make a difference, whether that means getting half again as many pixels to play with or getting sensels that are half again as large at the same resolution (or something in between). Whether or not that difference matters for your photography is another question with a different answer, but you don't get to answer for anyone else any more than they (or I) get to answer for you."
Ctein replies: Since we're dispelling myths and taking on "magical thinking".... Almost no aspect of image quality scales with the area of a sensor. They scale with the linear size of the sensor. So, yeah, it is kinda "magical" to compare areas and claim a marked superiority based on that. In other words, it's a 20% gain, not 45% gain, in your same-format example. Which is visible...but just barely (differences in any of the metrics below about 15% simply aren't). The full-sensor difference works out to about a 35% gain, which is visible...but variations in sensors and camera electronics within the same format can produce bigger differences than that. At best, you can say that "on average" across all makes and models, you'd see that gain. 'Cept no one buys an "average," they buy a specific instance.
Mike replies: I've typically been what Phil Davis dismissively called "an eyeballer," which admittedly is getting more problematic as my eyeballs get worse. However, I have to say I've been consistently impressed by big jumps in numbers of pixels, intermittently impressed by specific sensor implementation (i.e., my current Fuji X-Trans sensor is wildly better than the same size sensor in, say, the early Pentax *ist D), and frankly unimpressed by incremental differences in sensor size, which seldom gives me enough to float my boat. The old seat-of-the-pants rule-of-thumb for film formats was that you have to move up or down two sizes before you see clear and consistent differences, and I think that more or less holds true for digital as well—meaning, if you want to see clearly detectable improvements, you need to jump up two levels in sensor size. Going from 4/3 to APS-C or vice-versa just isn't going to be visible in pictures, consistently. See Moose's comments on this in the Comments section.
I've always held other aspects of sensor size are more important than absolute IQ—the angle of view of particular focal lengths (important, say, with the Leica M), the size of lenses, the size of viewfinders, and whether you want more d.o.f. or less more easily.
But, as Stan notes, we each get to decide for ourselves, ultimately.