positives and negatives on same roll?

Discussion in 'Black and White' started by george_russell|1, Mar 4, 2004.

  1. I am the rankest of ameteurs, but am having fun learning all
    about reversal processing black and white film. I just ran a roll of
    Ilford PanF through the Tmax reversal kit, and am totally stumped by
    what has come out of the tank...some of the pictures are positve,
    some negative, some both! All the pix were bracketed, the under-
    exposed are mostly negative, the one-stop over are nice looking
    positives, and the ones shot at the film's speed (50), are weird,
    some parts normal and some parts reversed. I went over the
    instructions several times, and am sure I timed and temp'ed
    everything correctly. If I could do this consistently, it might be
    practical, choosing some pix to be slides and some prints, but I
    don't know how I did it. I DID make a mixing error, and may have
    gotten a drop or two of the second developer into the first...could
    this have slightly fogged it and made a "solarized" look? Thanks to
    anyone who can figure this out!
     
  2. Are the positive images really positive? Sometimes if you view a B&W negative against a dark background it will appear positive, especially if viewed in a glancing light.
     
  3. I can't remember if the T-Max kit accomplishes the reversal by a light re-exposure or not. In this process, did you have to take the film out of the tank and re-expose it to light before using the second developer? If so, and if the light you used to re-expose was too bright, you could have easily "printed out" your film, which would give negative-like results. I didn't think it was possible until I managed to do it myself :) In my case, I had used a re-exposure that was simply too bright. Cutting down on the lamp brightness helped a lot.
     
  4. Yes, the TMax kit uses light for the reversal process: The magic minimum number is 800 footcandle-seconds -- About 8700 lux-seconds.

    Simply measure the light source with your exposure meter, and multiply the footcandle or lux value by the number of seconds to get the number of footcandle-seconds or lux-seconds.

    Alternately, you may want to do a chemical reversal: This is handy for roll film since it's done on the reel, without having to guess the light exposure on the reel. You can use the Ektachrome E6 reversal bath chemistry, which is surprisingly inexpensive -- Like $4.95 for a gallon at Adorama.

    Cheers!
    Dan Schwartz
     
  5. Will the e-6 reversal bath reverse black and white films? I've used a potassium permanganate bleach, and then exposed to light (presumably the same process as in the t-max kit), but this is hart to find and I don't have much of it. Have you used the e-6 reversal bath in for this purpose, and if so how does it work?

    also to georges original question, I don't think mixing the two developers would have any negative effect. They're pretty similar; in fact, you could use any developer really and get OK looking results.
    thanks

    -tadge
     
  6. Tadge:

    Yes, E6 reversal bath is supposed to work fine, in order to replace the light exposure reversal step between the first and second developers in the B&W reversal process. In fact, you can even use the first two E6 steps to process B&W film for reversal -- That's where I got the idea!

    Please see this thread for a full discussion:

    http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=007K4f

    -----

    You're confusing the bleaching step with the reversal step -- Yes, E6 (permangenate) bleach is horribly expensive: By the 5 gallon ready-to-use cubetainer it's over $22/gallon from Fuji Hunt; even more from Kodak.

    Cheers!

    Dan
     
  7. About all of these "rare" cases of partial and/or dual positive-negative processed films AND papers read the most comprehensive, scientifical text: http://www.cchem.berkeley.edu/~wljeme/SOUTLINE.html

    Closely related to the solarisation and other similar processes. Rergards. Eduardo.
     

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