Sincere thanks to all who offered advice re chromogenic B&W in E6. It is obvious that results would be well below par so I have elbowed the idea. I have decided to go down the most obvious alternative path - that of reversing a convential film such as PanF+, FP4+, or Tmax. If anyone has experience of this proceedure I would very much welcome any comments, suggestions or even formula, I know there are a few fomula already posted on many sites but any practical experiences would be great.

-- Chris Moyse (chris@cmoyse.freeserve.co.uk), February 25, 2000

Answers

Chris, welcome to the dark side. I, for one, reverse process well over half the black and white film that I shoot. I'll give you my experiences.

Of the films you mention, I have rejected both PanF and FP4 because of the base tint. I worked on reversing PanF for a while last summer and got OK results as far as contrast and tonal range go, but the base tint that Ilford builds into their film means that you will never get clear highlights. The tint is in the film base, it isn't a fog so there is nothing that you can do about it.

TMX has a nice clear film base, but I never got results that I liked. I first tried using the developer formulas that Deithrich published in 1988 (and which are available as a kit from Photographer's Formulary by the way) but ever got results that I liked so I started working with first developers of my own design. I still never got results that I liked and finally chalked it up to the t-grain emulsion. So, what was it I didn't like? The blacks never satisfied me. They were never dense enough and had a warm tone to them that looked an unappealing rusted color. Not a nice warm sepia or anything, just a muddy nasty look that I could never get past so I abandoned any further consideration of t-grain films.

The film I really like for reverse processing is Tech Pan. It has a number of characteristics/compromises that one has to accept, but if one shoots TechPan as a negative film, you have already made those compromises. The biggest one is slow speed. When I shoot TechPan for transparencies, I expose it at EI 12. As a result I almost always shoot from a tripod. You can get away with hand held shots if you have lots of light and/or have fast lenses and dont need lots of DOF, but I pretty much shoot from a tripod most days. A second consideration that one needs to take into account when shooting TechPan transparencies is the scene contrast. Using my protocols, TechPan shows a dynamic range of about eight to eight and a half stops from Dmax to clear film base. For your average scene of five to six stops of illumination, that is just right. However if you are shooting a scene such as one I shot the other day where I was shooting inside a barn with the doors open and wanting both the interior and exterior scene to record on film, reverse processed TechPan is not up to that job (I shot that scene on PanF as a negative and did and N-2 development to get it all on the film). But, once you accept the limitations of the film, TechPan makes for wonderful transparencies. The first developer that I generally use for TechPan is a 1 to 20 dilution of HC110 with 2 grams of sodium thiosulfate per liter of developer. I develope for 10 minutes at 20 deg C. I then bleach, clear, re-expose and develop pretty much as in any of the other protocols you will find on the web. My second developer is 1:10 HC110. The first developer will control such things as the contrast and density of the final slide. The second developer is where you control such things as the tone of the image (ie you can add sulfide to the second developer to warm the tone up, or even use straight sulfide for a sepia slide).

Another film that I have had good results with is Kodak's HIE. I recently bought a big double handful of the pre-production run of Maco IR820 and am trying to see if I can hammer out development protocols for that. We'll see if I like it as well as HIE.

One thing want to stress is that you will be better off experimenting and coming up with protocols specific to each film that you want to use. The EI, developer formula, and processing times that you arive at for one film probably wont be the optimal for another film so you will need to optimise them for each film to get the best results possible from each film. I do all of my initial work on a new film using a step tablet in order to determine the speed of the film and the contrast range I am getting. Once I work it out with a step tablet, then I go out and shoot test shots to see how it is working with real life scenes.

Go over to the photo.net forum and look up my past postings and you will find one from last fall or summer where I give links to the RIT PhotoFAQs that give formulae and protocols for reverse processing (even ones specific to PanF and FP4, and I think Deitrich's formulas might be there too). They will help you with the basics of reverse processing. Another place to look for information is old copies of the Photo Encyclopedia. The more recent ones have dropped the entries on reverse processing, but the older ones have information in them. Once you gather all your information then it is time to experiment and have fun.

I encourage your experimentation and wish you the best luck. There is something about a black and white slide that is unique and well worth the effort. Good luck.

-- Fritz M. Brown (brownf@idhw.state.id.us), February 25, 2000.

What do you think about reversing standard b&w negs as slides? I have used a bellows/macro setup to dupe onto Kodalith, developed in D76 with quite good results. Bracketing exposures is required as Kodalith is very sensitive to exposure.

-- John R. Fowler (cpc i@fox.nstn.ca), February 27, 2000.