black and white film as reversal
Can anyone tell me how can I ( if it is possible) develope common black and white film (in this case agfa apx 400) as a diapositive?
And how can this change the quality of the image?
In principle it's pretty simple -- you develop more or less normally (perhaps to higher contrast than you normally would) but without fixing, bleach away the developed image with a non-halogenating bleach (so the bleached silver is completely removed but undeveloped halide remains -- potassium dichromate is one common reversal bleach), then fog the remaining halide with light or chemicals and redevelop, followed by normal fixing (and a few extra wash steps various places in that sequence to prevent carry over). Once you get the right conditions for EI and first developer, you get nice B&W positive transparencies, frequently at higher EI than would be the case with negatives for printing.
Originally Posted by adrian_freire
In practice, it's a bit more complicated -- you have to be concerned about undevelopable silver in the highlights showing up as dark fog after reversal, you have to shoot a lot of tests to get the right combination of EI and first dev, and everything works backward from negatives so you're likely to make a relatively high number of mistakes in getting the process right -- and then you have to start all over if you switch films or first developers (though the rest of the process is carried to completion on all steps and is relatively tolerant).
Quality of the image is affected by the developers used (both of them), and by the fact that projected images are typically magnified much more than prints would be (though that's offset by the fact that they aren't viewed at arm's length when projected), and as with any other process, different films and first developers will give different characters to the image. Panatomic-X used to be the standard film for B&W reversal, but now Kodak's reversal kit is aimed mainly at T-Max 100 -- not a coincidence that those are and were the finest grained films of their era. DR5 does reversals of Tech Pan (if you still have any) that, from what I've seen, are very nice indeed, with the twist that redevelopment can be selected as either neutral or sepia. In practice, however, any B&W material can be reversed -- the question is what the final image will look like, and what look you want.
Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.
Contact Photo Technniques magazine. They have a back issue that describes the process (some time in the last 3 years I think). You can purchase the back issue, or you could possibly find it in your local library.
Fotoimpex in Berlin sell a reversal kit. www.fotoimpex.de
Digital is best taken with a grain of silver.
Donald gave a good starters description what happens in reversal and Hans is right, the reversal kit made by Foma, sold by Fotoimpex in Berlin is the easiest way to DIY bw slides.
As still many people had problems with it - it´s more than slightly more complicated than dunking a roll of film in Rodinal -, I wrote a step-by-step instruction together with a friend, dealing with "how to set up, how to test films" etc. At this moment it´s only in german, the english translation is ...errrh... a tiny bit delayed. ,-)
I wouldn´t use APX400, it still has a slight greybase which dampens the visual contrast. Go with APX100, it comes out allmost as good as the Foma bw reversal film and Agfa Scala.
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Or contact print the negative to another piece of film. If 35mm then use a slide copier on the front of your camera and shoot traditional or ortho film.
Kodak used to make a copy film but I'm not sure if it is still available.
The film Eric refers to may be the old Kodak High Contrast Copy. It was available in 35mm and worked great for making positive slides from B & W negatives. If I recall correctly, development was in D-19 with Dektol (maybe 1:1 or 1:2) a possible alternative. I suspect that Technical Pan would also work well for positive slides, but I haven't tried it.
The copy approach is, in my opinion, preferable to doing chemical reversal. The positive can be made from any size negative; a negative is still available for standard printing; some adjustment can be made for under- or over-exposed negatives; cropping is easily done; and, if necessary, multiple slides can be made from a single negative. Finally, any errors in exposure or processing can be overcome with a re-shoot.
I don't know if APX 400 would reverse well in a conventional reversal process. Copying the negatives onto a duplicating film would be the best bet. Tech Pan or Kodak 5302 work well. Have a look here: http://www.photosensitive.ca/BWslides.shtml for an article I wrote a couple of years ago summarizing B&W slide options.
Thanks, this is the first time I use this forum and I´m amazed, is a great tool for all the traditional Photography lovers. Things like this help us to enjoy more photography.
(Excuse me for my wrong english)
I just saw my first Scala slide at a Camera Club of Ottawa
meeting a few weeks ago and I must say, after all the eye blazing colour slides and digital things, it was a real relief to look at a large, projected black and white image.
I did some looking around for a cheap and easy alternative to Scala and Ilford has a PDF on their site with instructions on how to reverse their films.