Yesterday I ran a set of BTZS type tests of some J&C Classic 200 film. Five step wedges were given identical exposures, timed with a Metrolux light integrator, and each one was then developed for a different amount of time in a 22:100 dilution of Pyrocat-HD, in BTZS type tubes using constant agitation in a water-bath. I subsequently read the negative densities through the Visual, Blue and UV channels of my densitometer, and finished by plotting the curves with WinPlotter.
Consensus opinion on this list and in other forums seems to be that the J&C Classic 200 film is same as Bergger BPF. For that reason I based my exposure and development times on previous tests of BPF film, which turned out to be too long to provide me with as much information as I like to get from this type of testing. However, a comparison of the results from testing of the two films showed some interesting differences. I donít have any idea who really makes these two films, but if they are made by the same company there are some substantial quality control issues involved.
BPF 200 and J&C Classic 200 are similar in that both are thick emulsion films that respond well to Pyro developers. And both give off in the pre-soak water the same blue/green dye from the anti-halation layer. But that is about it for the similarities.
The fundamental differences I observe from the tests are.
1) J&C Classic 200 develops to a given CI much faster than BPF200. For development to a density range of 1.60 (UV reading) for a SBR of 7, BPF 200 needed about 9 minutes of development at 70F, J&C Classic only 4:30 minutes.
2) J&C has a higher effective film speed than BPF 200. With development of J&C film for alternative processes I would recommend using the recommended film speed of 200 for use in the field. By contrast, BPF 200 needs to be rated at about EI 100, even when processing to a high CI, and even lower if developing for silver gelatin printing..
3) J&C 200 will develop to a higher maximum CI than BPF 200. With Pyrocat-HD used at the 2:2:100 dilution at 70F I was able to get a maximum gradient of about 0.95 with 9 minutes of development with J&C Classic 200. By contrast, BPF reached a maximum gradient of only about 0.80 at 20 minutes of development. This suggests that J&C Classic 200 would be a much better film than BPF 200 for use in low contrast scenes, especially with negatives meant for alternative printing.
For dual purpose negatives such as AZO and PT./PD, or AZO and Carbon, or AZO and Kallitype, Pyrocat-HD and J&C Classic 200 are a very nice combination. A negative developed to a DR of about 1.3 for AZO will have a much higher effective DR with alternative processes that use UV light because of the increased filtration of this light by the stain, so it would work well for a process such as palladium that has a paper ES of about 1.75.
What I would recommend in terms of development of the J&C Classic 200, using Pyrocat-HD 2:2:100, for AZO and Palladium printing, is the following.
SBR 7.5 3:30 minutes
SBR 7 4:30 minutes
SBR 6 7 minutes
SBR 5.5 9 minutes
Of course, these are ballpark figures so be sure to test first before developing important negatives.
Because of the short development times with the 2:2:100 dilution some might well prefer to use the 1:1:100 dilution, especially if working in SBR conditions over 8. Unfortunately I just had a few sheets of the J&C 200 film to test and canít provide any further data at this time.
Thank you for taking the time to do the testing and to share the results. I for one appreciate your efforts.
I hope the information is useful to you.
Two more quick notes about the tests.
1. The recommended target density range of 1.3 for AZO printing, which will translate into an effective DR of about 1.7 for UV processes, should be based on a blue channel reading.
2. Times are based on rotary develoment in tubes, with constant agitation. For tray development with intermittent agitation increase all times by about 15-20%.
Serendipitous posting!! I am just about to commence my first attempts at Pt/Pd printing and Classic 200 is one of the films I am intending to use..... Thank you Sandy for generously posting your data.
I second the gratitude being offered. I'm now using pyrocat with Tri-x 320 at 2:2:100 in my Jobo and couldn't be happier. the prints, mostly from 5x7 and printed on Bergger VCCB, are the finest I've ever produced. My print exposure times have been halved, compared to Rollo Pyro and I am no longer concerned about uneven staining of the negative.
Unlike some of the "purists" you recognize the advantages of the Jobo and allows me to "steal" the results of your testing with very little adjustment. This really helps the weekend photographer.
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Not only the weekend photographer, I have literally stolen Clay and Sandy`s data and have it taped on a board in my darkroom. :P
Originally Posted by Tom Duffy
But remember that the data on J&C Classic 200 film represents my first testing oif this film, and is not backed up by any field testing.
And there may be consistency issues. It is my understanding that both Bergger BPF and the J&C film are made at the same plant. Are the differences between the two due to some tweaking of the emulsion, or are they due to other factors such as aging, quality control, etc? Only more experience in working with the film can answer these questions.
Sandy, thanks for posting these results, which I imagine are useful to many.
If the differences between JandC and Bergger are, in fact, due to quality control problems, rather than intentional emulsion "tweaking," they are pretty profound quality control problems. In that case, I guess we'd expect to see extreme consistency problems in the behavior of different lots of these films. (In fact, variations of this magnitude--nearly 100% in developing time--would make these films pretty much unusable, at least to me.)
Has anybody who uses either of these films regularly observed such a thing?
While my first order of Classic 200 is enroute at this time, I have used Bergger BPF 200 for some time and I have not encountered any such inconsistencies in my experience. The things which Sandy described about BPF 200 have been my experience (will not expand to the degree that the Classic seems to have in his testing) The film speed on the Bergger film with ABC is 80.
Sandy, thanks for sharing your data!
WRT Bergger and J&C Classic... On another forum John Horway (not sure if I spelled his name correctly - sorry John) commented that while both films are made at the same plant, they are made to different formulations. The formulation used by Bergger is "proprietary." I don't know how true that is, but Sandy's results bear this out.