Film/developer testing at Kodak and Ilford
Hopefully PE and Simon will write in on this one.
Over the years as I've tested and practiced with various film/developer combinations, it always struck me how time consuming it is, and how much care is involved in carrying out exhaustive experimental testing leading to meaningful, repeatable results. It requires much repetition, and careful monitoring of variables.
I've often wondered, how exactly was this carried out at companies like Kodak and Ilford (in the days before research stopped of course). For example, when a new developer is formulated: never mind the laborious work of testing during the formulation or R&D phase, but what about even after that, when the formulation is complete and developing times and agitation scheme instructions need to be determined for a whole list of films, in different formats? How was this actually done? In the heyday, were there actually teams of people developing film all day in small tanks, large tanks, roll film, sheet film etc etc over and over again? How many times would something be repeated until it was determined to be an experimentally significant result? Do EK and Ilford actually have facilities where people spent most of their time developing film under controlled conditions, at all the different temperatures, for different contrasts, dilutions, and on and on?
And what about all the research papers from people like Henn, James etc etc you read about referenced in summary books like Anchell/Troop? Did these big guys have employees working for them testing materials all day? Would those people be grad students, or junior employees? I think I would have enjoyed that sort of grunt work actually.
B&W development times are just suggested starting points, so I don't suspect they labored too much over it. Color was probably a different situation.
"Note: The development times in the table are suggested starting points
." from KODAK PROFESSIONAL T-MAX Films • F-4016
Last edited by ic-racer; 10-11-2011 at 06:39 PM. Click to view previous post history.
In my experience the suggested times vary from pretty good to wildly wrong in both Kodak and Ilford literature, but I still find it hard to believe they didn't work hard on it. The only reference to this sort of thing I have in my books appears in Anchell/Troop on the subject of XTOL times. Apparently, at least for that particular developer, there was a lot of rigorous testing, directly supervised by XTOL's formulators. But perhaps in other cases you are right - maybe the instructions are based more on extrapolation rather than brute force testing.
But even if we go beyond instruction sheets, I'm also referring to testing done to support all the research papers that came out of these companies regarding everything from sharpness to grain, contrast, etc etc.
Last edited by Michael R 1974; 10-11-2011 at 05:12 PM. Click to view previous post history.
If you look at the info on a "newish" developer like Xtol it seems pretty extensive to me, covering a large range of films and rotary processing. The impression I get is that Kodak was pretty thorough in its research.
Last time we visited Ilford, there was still an active research dept and if its ongoing strict QC is anything to go by I'd be surprised if Ilford was in any way "winging it" in terms of films and developer information.
Having said that I note that one film in particular, one of its latest, namely D3200, has a reputation for needing the times for the next speed up.
I have no idea whether there is a similar Kodak film for which user developing experience diverges from Kodak's recommendation.
Don't get me wrong I'm not talking about quality control on the products themselves. Ilford and Kodak products are first rate.
I didn't want to make this about how right or wrong things like suggested developing times are, but since you asked, I've personally experienced some of the suggested starting times for both Ilford and Kodak products being way off. I'm happy to share my own results, but I'm not sure if I want the thread to go in that direction because developing times can vary significantly from person to person based on how well temperature is controlled, different agitation schemes, accuracy of measurements, testing methodology and on and on. That's why even when my personal times are way off I hesitate to say the suggested times are "wrong".
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In addition to all their lab testing, Kodak used to make fully equipped darkrooms (both colour and black and white) available to their employees. All the equipment and chemistry was supplied.
So they had a built in testing force available as well.
EDIT: at least at their major lab sites (like Toronto in Canada)
“Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”
Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2
If you watch the 1950s Kodak industrial documentary "How Film is Made" you can see them testing some film and plotting an H&D curve. You can watch it via the APUG media page.
The manufacturers post curves. The recommended "times" are based on a set of conditions that are usually listed. For Kodak, it is either CI 0.56 or 0.58 which is normal for a grade two paper with a diffusion enlarger under average conditions. If you're conditions are different, check the CI / Time curves.
The manufacturers aren't wrong. The times just might not be right for your conditions and the way you work.
There was a good discussion of the testing done in the early years of Kodak research in a non technical retorspective 'from Wratten to Ektachrome' or something like that.
It was written by committee on retirement or the first director of Kodak research labs. whose name escapes me at the moment. Not Mees, but his presicessor I think.
my real name, imagine that.
Stephen, that's why I didn't want to make this a discussion on how "right" or "wrong" the published instructions are. I'm interested more in how the actual testing work was done from a manpower perspective.