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  1. #11

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    Alessandro --

    My comments, as before, are as follows:

    (1) I think you are underexposing your film. I seem to recall that Kodak, in their T-MAX reversal process, recommends that the film be exposed at EI 50.

    (2) Your bleach recipe seems under-acidifed relative to what I use. Have a look here:
    http://www.angelfire.com/wi/spqrspqr...wreversal.html
    There they recommend around 55 g/litre of sodium bisulfate for the "B" part of the bleach. I'm not sure if this will make a big difference in your bleaching times.

    (3) If this step fails, I'm not sure what to suggest. Is the Tetenal hardener meant to be used alone, or added to fixer? I ask because its action may be pH-dependent.

    (4) If all of these fail, maybe you need to try dichromate bleach and see if that fixes the problem.

  2. #12

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    Actually, in reading through the reversal recipe on the Photographer's Formulary web site (here: http://www.photoformulary.com/uploads/01-0600.DOC) they use the same reversal bleach composition as you (from the Dietrich article in Photo Techniques in the late 80s). So I'm not sure what's going on here.

  3. #13
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    A couple suggestions. First, if you add an alum hardener to the fixer, the fixer must be acidic. Your fixer, made with thiosulfate, sulfite, and metabisulfite, is probably very slightly alkaline. Add some acetic acid to the fixer and you'll stop the clouding, though it's probably better to abandon hardener in the fixer in favor of correcting the pre-bleach hardening bath. The hardener alone in the the pre-bleach bath is probably doing nothing if the solution isn't acid; use stop bath strength acetic acid in place of plain water if the hardener concentrate itself isn't notably acidic. Correcting the pre-bleach hardener to be acidic, so the alum can actually harden the emulsion, will likely help considerably with the reticulation, though it may also require lengthening the bleach, clearing bath, second dev, and fixing, and especially washing.

    What you describe as dark slides may mean you need more silver solvent in your first developer (fog) or that you need to develop longer in the existing first dev (underdeveloped). Underexposed isn't very likely; most B&W negative films gain speed in a correctly working reversal process (many years ago, Panatomic X had to be exposed at EI 64-80 for reversal, where 25-32 was normal for negatives).
    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.

  4. #14

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    A new try in a few days...

    Quote Originally Posted by Jordan
    Alessandro --

    My comments, as before, are as follows:

    (1) I think you are underexposing your film. I seem to recall that Kodak, in their T-MAX reversal process, recommends that the film be exposed at EI 50.

    (2) Your bleach recipe seems under-acidifed relative to what I use. Have a look here:
    http://www.angelfire.com/wi/spqrspqr...wreversal.html
    There they recommend around 55 g/litre of sodium bisulfate for the "B" part of the bleach. I'm not sure if this will make a big difference in your bleaching times.

    (3) If this step fails, I'm not sure what to suggest. Is the Tetenal hardener meant to be used alone, or added to fixer? I ask because its action may be pH-dependent.

    (4) If all of these fail, maybe you need to try dichromate bleach and see if that fixes the problem.

    1) Probably you're right: I'm underexposing the film in relation to how much hypo I'm using in the first dev;

    2) I took that recipe from the Photographer's Formulary T-Max reversal processing kit, which calls explicitily for 34.5g of sodium bisulfate for 1 liter.
    This kit was after the March/April Darkroom Techniques issue of Mr. Dietrich;

    3) The Tetenal hardener is meant to be used in a fixer. I think much better results comes from using Formalin as per Kodak SH-1 recipe, present in Kodak Pub. J-1; but since I haven't formalin I can't do the pre-hardener bath before the bleach so I'll try again with a simple hardening fixer as last resort; In September, when I'll have access to my local chemistry shop, I'll do some other tests with formalin; I think this is the MOST IMPORTANT step to insure a full quality reversed slide;

    4) Never in my life I'll touch dichromate (it's too dangerous and isn't worth the candle - not that formalin is less dangerous though... )

  5. #15
    nze
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    I use a formol bath to harden the film. but alun should work too.

    to get good slide it is better to overexpose your film for a about 2 stops.

    I add sodium sulfocyanure to the first developper, it hep to keep fog low with the following step of the inversion

    May you try this , first exposse the T max @25 iso
    Then you may develop first with PQ ilford 1+9 +9.5gm sodium sufocyanure added by each liter. Dev time 8.5 min@20°C.

    Then harden your film iin
    Formol 37% 15ml
    sodium carbonate 5g
    Water to make 1l

    for 2 minutes
    then follow all the other step till the lasst deelopment then instead of D19 you may use PQ @1+4 with no sulfosyanure added.

    regards
    Chris Nze
    me Apug Portfolio
    Me web page

  6. #16

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    Quote Originally Posted by Donald Qualls
    Your fixer, made with thiosulfate, sulfite, and metabisulfite, is probably very slightly alkaline
    Quote Originally Posted by Gerald Koch
    The 25 grams of sodium metabisulfite already makes the fixer quite acid and the hardener causes the pH to drop even lower
    Who is right?



    Quote Originally Posted by Donald Qualls
    Add some acetic acid to the fixer and you'll stop the clouding,[...]
    The Tetenal hardener already has acetic acid into it.



    Quote Originally Posted by Donald Qualls
    [...] though it's probably better to abandon hardener in the fixer in favor of correcting the pre-bleach hardening bath. The hardener alone in the the pre-bleach bath is probably doing nothing if the solution isn't acid; use stop bath strength acetic acid in place of plain water if the hardener concentrate itself isn't notably acidic. Correcting the pre-bleach hardener to be acidic, so the alum can actually harden the emulsion, will likely help considerably with the reticulation [...]
    I've used the Tetenal hardener alone and since it contains acetic acid I've used the hardener as a stand-alone stop bath between the first developer and the bleach (with a copious water bath after the hardener) but the reticulation still exists.

    On the Tetenal hardener bottle there's explicitily written: Hardener for fixer bath, so I'm assuming that the hardener coundn't used alone.

    With what I'm left?


    Donald: have you conducted your own tests? I really want to know how you do the reversal process, maybe there's something I forget to do.

  7. #17

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    Alessandro, the basics of your process are correct, and the use of Kodak D-19 as the basis for a reversal first developer is well-documented in the photography literature. The "sodium sulfocyanure" that NZE refers to is known in English as sodium thiocyanate, it is an alternative silver halide solvent that you can use if you want to. The effect is the same, but sodium thiocyanate works at lower concentrations, but is more expensive and harder to use. Thiosulfate is fine, but you should mix it into the developer right before use (don't let it stand).

    The response of films to the reversal process differs. Panatomic X might get a speed boost, but Kodak clearly states in their literature for the TMAX Reversal Kit (see here: http://www.kodak.com/global/en/profe.../j87/j87.jhtml) that TMX needs a one-stop overexposure for "normal" results in the reversal process.

    As far as the hardening is concerned, I'm not sure what to recommend. I think some small E-6 kits contain formalin stabilizers as the last bath. Maybe you could use one of those?

  8. #18
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    Quote Originally Posted by Alessandro Serrao
    Donald: have you conducted your own tests? I really want to know how you do the reversal process, maybe there's something I forget to do.
    Not being familiar with the Tetenal hardener, I wasn't sure if it was acidic or just a plain alum solution, perhaps buffered to prevent it becoming alkaline and precipitating an insoluble aluminum salt.

    Given that the hardener incorporates acetic acid, there shouldn't be a problem with using it in either step where you do, but that doesn't explain the clouding of the fixer when you add the hardener -- it shouldn't do this.

    I haven't yet managed to do B&W reversal myself -- I've been prioritizing getting my printing setup in line, and am just about there; should be able to print this weekend. Beyond that, then, I'll need to obtain some bleach (probably copper sulfate, since it's easy to get and cheap, along with battery acid), and start working out the right ratio of fixer concentrate, additional alkali, and HC-110 or Dektol for first dev (I use HC-110 for everything but prints). I'll most likely work in sheet film, at least until I have the process completely under control, because shooting one sheet and developing is a lot faster and easier (and cheaper) than burning a whole roll of 35 mm or 120.

    My main aim with B&W reversal, however, is to shoot in-camera direct paper positives for a "one of a kind" image, similar to Polaroid but larger and cheaper. This will almost certainly work out with different needs and values than images intended for projection.
    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.

  9. #19

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    Alessandro,

    What are the instructions for the Tetenal Hardener? Are you using it correctly? If they say to add it to a plain hypo solution then you are not following the directions. What you are starting with is a non hardening FIXER which alread contains, besides thiosulfate, sodium sulfite and sodium metabisulfite. For example, if you would look up the formula for Kodak F-5a Hardener you would see that it says to add the hardener to a 30% solution of sodium thiosulfate. No mention of added metabisulfite or sulfite. This is why I say that your resulting solution is too acidic causing the sulfurization.

    Film intended for reversal is usually shot at an EI above the manufacturer's rated speed. If you fail to do this the slides will be very dark.

    If you can obtain some chrome alum (potassium chromium sulfate) it is a much better hardener than ordinary alum. Use a 3% solution for 3 to 5 minutes as a hardening stopbath. This should harden the film enough that a hardening fixer is not required.

    As far as using potassium dichromate this is safe to use, as are all commonly used photochemicals, if some care is observed. I certainly consider it safer than pyrogallol and catchol which are in common use as developing agents.

    Jerry

  10. #20

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    Quote Originally Posted by Donald Qualls
    Given that the hardener incorporates acetic acid, there shouldn't be a problem with using it in either step where you do, but that doesn't explain the clouding of the fixer when you add the hardener -- it shouldn't do this..
    For what I've understood, low pH causes the precipitation of the colloidal sulfur. I'm guessing this was the case.

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