My column last week about mysterious out-of-focus areas in a series of my photographs brought forth many useful and interesting suggestions from readers for experiments I might do to further pin down the cause of the problem.
I encountered only one small difficulty with these: the problem wasn't repeatable! I had 10 photographs with profoundly defocused areas, and that was it. Nothing before and nothing since. Makes it more than a little difficult to investigate further.
Mind you, I and those readers could (and did) do an awful lot of data-mining from the existing photographs. We could eliminate many possible sources for the problem from the available evidence and narrow it down to a few plausible ones. That, though, was as far as I could take it. I may never know the answer...unless the problem resurfaces in a way that lets me either test it further or get equipment repaired. If repairs are what is needed; even that isn't obvious.
This is one of the (many) reasons why doing useful photographic research is hard. Often the things you want to investigate, especially the problem areas, don't cooperate by appearing at your beck and call. That doesn't necessarily mean they are random or inexplicable occurrences, just that you don't know how to control the situation well enough to force them to appear reliably (or, more usefully, make them never appear).
This afflicts even the best researchers with the most well-equipped labs. Most of the major research I've undertaken over my photographic career has proven somewhat controversial for precisely that reason. Other people may not see the same results or have the same experience as I do. That doesn't make my research invalid, but it can make it very difficult to validate.
Likely the most famous example of that is my study into the cause of bronzing and silvering-out in RC black-and-white photographic papers, to which I devote considerable pages in my book Post Exposure, available free online. I'm not going to detail the research here; you can read my deathless prose in the downloadable book. The essence of it is that those papers are susceptible to damage because they generate their own reactive compounds under exposure to light. The damage can be entirely prevented (well, so far; it's only been 16 years) by very, very light selenium toning or treatment with a preservative solution that used to be sold by Agfa called Sistan.
That's it in a nutshell. Should be pretty easy to check out, right? And, indeed, when I published my results, Agfa, Kodak, and Ilford all paid them considerable attention (I do have some credibility). Agfa readily confirmed the self-oxidation problem and publicly acknowledged it, even going so far as to recall and suspend production of certain papers while they worked on reformulating them.
Kodak was less forthcoming about the matter. In private conversations with me they were happy to say that they agreed with my results. Publicly, they decided the less said the better.
Ilford was the major holdout. They persisted in the belief that there were no inherent problems with these papers and that any bronzing or silvering out could be attributed to poor processing or environmental damage. These were known to be problems; when Gary Mortensen was still running the photo department at the Minneapolis Institute of Arts, he showed me Ilford Multigrade IV RC prints that had clearly suffered damage from chemical compounds in the air. Some sort of "sick building syndrome" for photographs was at work. They had hundreds of these and it was most clear that RC black-and-white prints were not stable in the MIA's environment.
Ilford, though, would not admit that there was anything innately problematical about the materials. It was all bad processing or bad environment. They had a good reason for doing so. They had tried to replicate my results. They couldn't get the prints to deteriorate under exposure to light. It just wouldn't happen for them at all. What else were they going to do? It's not just that it's difficult to acknowledge a problem you can't make appear, though that's true enough. Had the roles been reversed, I'd have been skeptical. It's that if you do acknowledge it there's still absolutely nothing you can do about it! How do you eliminate a problem when you can't make it show up in the first place?
Inferentially, there must be other factors involved besides simple light exposure. That's not only supported by my and Ilford's results, but by photographers' real world experiences. Many photographers have experienced the silvering-out problem; many others haven't. Very few experienced it as reliably as I did. Without that reliability, testing different conditions to isolate the causative factors becomes nearly impossible. I happened to be the right person in the right place. Lucky me.
Ilford and I never did figure out why I was so "lucky" and they so extremely "unlucky." Like my fuzzy photographs last week, we'll probably never will figure out just why some properly-processed RC prints are subject to self-deterioration and others aren't.
Photography, like all of life, is filled with many mysteries. One must get used to living with a certain amount of uncertainty.
Ctein's weekly column on TOP appears with adequate but not absolute reliability on Wednesdays.
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(To see all the comments, click on the "Comments" link below.)
Featured Comments from:
John Robinson: "I'm a software developer. A lot of software developers hate 'debugging'...but I love it. It is more science, than mathematics, because it is all about experiments. If you can't reproduce the problem, then its harder, and I like it more...that's just me.
"The most difficult problems are the ones for which the detection is farther away from the cause in time...in fact, the farther away the manifestation is from the discovery, the more difficult the problem is. Debugging is about guessing, and then building tests that will prove, conclusively, that the guess is wrong. You can never really prove it is right...but you can, in learning to reproduce the problem, prove definitely that your hypothesis was wrong. If you can not reproduce the problem, then you have to debug it 'in the wild.' Those are my favorites...also the most difficult.
"I have no idea what caused the problem you observed...my best guess would be some atmospheric (non-camera) phenomena...I would suggest returning to the same place on the same day of the week, or same day of the month, to see if it re-appears. Not easy, I know.
"And, as with all debugging, sometimes, you just want to know it doesn't happen all the time...then you'll keep an eye on it...wait for it to happen again...if it starts to happen a lot, then the priority goes up...otherwise its just one of those mysterious things....
"Life is full of mysteries...one of my favorites is 'why are there any rules at all?' Said another way, we humans tend to view order as a sign of intelligence. I'm not a big believer in God, or 'Intelligent Design,' but the fact that there is a mathematical equation that can reproduce the shape of a fern is, to me, incredibly profound...I don't know why this is, but accident is not the item at the top of my list.
"One of my favorite stories, from a friend, is of a woman who complained that her word processor (yes, this is going back a bit) was inserting long strings of random spaces in her documents. Several technician visits failed to uncover the malfunction. But the next time the problem was reported, another technician was dispatched. Rather than intervene, he just observed. Basically, he said, 'show me this problem.' The demonstration led to the observation that from time to time the woman's ample breasts were depressing the space bar, unbeknownst to her.
"Sometimes, very simple, obvious problems, take a long time to solve...because they're only simple, and obvious, once you have all the information."
J: "When I used to work at Lick Observatory on Mt. Hamilton (45 years ago), we used to sit on the wall overlooking the Bay Area enjoying the view of the lights along the Bay as the sun set (or rose). I remember the twinkling of the lights in the unstable evening air and the wisps of fog floating along the shore. We would wait hours for the air to stabilize before observations would begin. I guess you see where I'm heading with this...."
Ctein replies: This was covered in the previous column, but since you posted the comments here…. Atmospheric distortion does not jump around in such a way that when you're doing a panoramic sequence it only shows up in the right 25% of each frame and does so in each and every frame consistently. Well, not unless the gods are really out to get you! If it's a divine malevolence, not much I'm going to be able to do about it.
Bruce: "I repaired Olympus cameras for 20 years. I can...er, could...pull an OM-1 apart in my sleep. My biggest problem by far was when a camera came in with a fault, supported by negatives, but it was not reproducible. Drove us stark raving mad. Ctein has beautifully summarised the dilemmas we had in the repair industry. (I'm now out, selling cameras retail, and having a ball trying out all the goodies which come into the shop.)
"I have my own theory as to why the image is unsharp. Many of the posted comments are worthy, but not supported by facts. Without being at the place of taking, knowing the camera settings, it's very difficult to diagnose the problem. It really is a "glitch" until it occurs again. (See real meaning of 'glitch' here—I heard it first from the Apollo space program in the '60s.
"My Canon 7D with 24–105mm gave intermittently unsharp pix in my aerial photos for a month, then miraculously cured itself. Still dunno why. Has never happened again. Ahh, the mysteries of the Universe."
psu: "I also work in software, which means that most of what I do is dealing with what I have done wrong six months ago. On the topic of debugging: one of the best discussions of debugging ever put to paper is in the classic Tracy Kidder book The Soul Of A New Machine about a team of engineers designing and building a new computer in the late '70s. The chapter called 'The Case of the Missing Nand Gate' is a veritable reference manual on what you do to find those awful intermittent bugs.
"Oh. And even though the book is about a 30-year-old computer that you've never heard of, it will teach you more about computers than any other lay-person-readable text in the world. I'll pay you back if it doesn't."
Mike adds: I agree—one of the great books of the present era and a must-read for everyone, young or old, smart or slow, computer geek or normal civilian.