I recently wanted to pull some 400ASA film (mixture of HP5+ and Delta400) a couple of stops. The problem with pull development is that manipulations with a standard developer (eg D76 and using shorter dev. times) does more to decrease gamma rather than the real speed of the film.

I tried Agfa's Atomal FF developer, as this was recommended to me, but with less than positive results. Grain and sharpness we not significantly better than these films would produce with dev to normal speeds (at least to my eye, though others may have a different opinion), and certainly no where near as good as Delta 100 or FP4+.

Does anyone have an opinion or comment on ways to get decent negs (ie normal contrast, say 0.55 or 0.6, and withoug destroying sharpness) when pulling a film by up to 2 stops, and any comments on the Atomal FF developer? Are there any home brews that are good for pull development?

Thanks

George

-- George Paltoglou (stellar@optusnet.com.au), April 25, 2001

Answers

No comments on Atomal FF, but if you want a real gain in speed rather than in gamma, your best bet might be a two-bath developer, such as Tetenal Emofin. This is said to produce about a one-stop increase in actual speed.

Regards, Thomas Wollstein

-- Thomas Wollstein (thomas_wollstein@web.de), April 25, 2001.

Don't know about Atomal. I remember David Kachel referred to something about speedwise bleaching (the Sterry method?) as the way to get a true decrease in speed i.e., without affecting contrast. If memory serves me right, he talked of a pottasium dichromate and acid bath being used as a bleach. Let me know if you are interested and I'll try to dig out the references. I guess an off the shelf approach would be to develop normally and use a cutting reducer like Farmer's. Cheers, DJ.

-- N Dhananjay (ndhanu@umich.edu), April 25, 2001.

Microdol-X or Perceptol undiluted will drop film speed about a stop. At any rate overexposing silver image B&W film will increase grain and reduce sharpness. No way around it. Why fight the film's natural characteristic?

-- Tim Brown (brownt@flash.net), April 25, 2001.

It seems to me that you are asking if there is a developer that can give normal gamma and contrast to film that has been overexposed by two stops. You do NOT wish to do an N-2 development? I am not aware of a developer that can do this.

The Sterry method mentioned above is a means of reducing contrast without loss of film speed by bleaching the film prior to development. I have an article on it entitled "Latent Image Bleaching" on my site at http://unblinkingeye.com/Articles/LatentImageBleach/latent imagebleach.html. But I don't think it is the answer you are looking for.

-- Ed Buffaloe (edb@unblinkingeye.com), April 25, 2001.

Ed, the Sterry method actually encompasses two methods - contrawise and speedwise bleaching. Contrawise bleaching does what you suggest i.e., alter contrast without altering speed, while speedwise bleaching alters speed without altering contrast. I should add that this is what I remember from Kachel's article in DCCT - I've never done any speedwise bleaching myself. Cheers, DJ.

-- N Dhananjay (ndhanu@umich.edu), April 25, 2001.