More questions about B&W reversal processing

Discussion in 'B&W: Film, Paper, Chemistry' started by cinejerk, Jun 11, 2012.

  1. cinejerk

    cinejerk Member

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    I've been playing around with black and white reversal processing. Right now I'm trying some old 16mm movie film and I'm seeing really thin dmax.

    Here is the run down on the chemistry. For first developer I'm using D-19 with 2g sodium thiocyanate. Bleach is chromate sulfuric. Then a sulfite clearing bath. Second developer right now is dektol. Then fixer.

    I guess my main question is what influences dmax the most in this type of process?

    There are a lot of variables here so I can't expect to pin it down exactly but some ideas might help.

    Using this exact same chemistry I have had much better results with a different film.
    Possibly my chemistry is getting weak, I don't know.
     
  2. Gerald C Koch

    Gerald C Koch Member

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    Old film which would produce a lot of fog when processed as a negative will produce a thin positive. Remember everything is backwards when doing reversal processing.
     
  3. johnielvis

    johnielvis Member

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    1st developer too hot or too long..."hot" includes too much silver solvant--I've found that they hypo in the first developer is not needed other than to speed up the process...it may add some speed...I dunno--never used it never needed to.

    tone down your first developer for sure--it's in too long with that hypo in there and it's getting eaten away before it develops...
     
  4. cinejerk

    cinejerk Member

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    Hi Gerald and John

    I think you guys hit the problem on the head. I processed a clip of the film with just first developer and then to the fixer.
    Came out really foggy.

    John I am using thiocyanate in the first developer. In a way I guess that is acting like hypo.

    Do you think there might be some kind of compromise that I can try to improve this a little?

    Maybe a little less exposure and a little less time in the first developer?

    What would anti-fog do? Probably do the same as less first dev time.
     
  5. Gerald C Koch

    Gerald C Koch Member

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    If your film came out really foggy as you say then there is no way to really salvage it. If you add enough antifog to eliminate a serious fog problem the film speed is also reduced. There does come a time when old film needs to be discarded. :sad:
     
  6. Chris Douglas

    Chris Douglas Member

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    Your film is fogged, Kodak has 16mm tri-x at a good price on their web site. I had about 1000 feet of old film and it was badly fogged, useless except for testing fixer clearing time. I have been taking movies with the tri-x, but it is easy to over expose, which gives a very thin positive. I'm using the H-7 process with a Morse rewind tank. Have fun experimenting.
     
  7. cinejerk

    cinejerk Member

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    Hi Chris
    Yep it's probably time to buy some film.
    I tried to reduce the first developer time and the positives just started getting really foggy.
    My initial point is probably as good as it will get.
    The images are there it's just the blacks are not as black as they should be.
     
  8. johnielvis

    johnielvis Member

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    starting with good film is first for sure...you may want to just get a minolta 16 and experiment with that rather than running long batches, you know...then again I don't know how your processer is--the small strips of minolta 16 can be delveoped in a tube/pipe easily if you don't have the teeny reels for 110....then when you get your process down you can move up to REAL film burning...
     
  9. cinejerk

    cinejerk Member

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    Hi John
    Yes that's exactly what I have, the minolta 16. I reload those tiny plastic cassettes.

    But I find that I can just buzz off a foot or so of film in my bolex. Then cut off that piece in a dark bag and
    load it into my yankee clipper roll tank.

    I actually find that faster then messing with the little minolta.
     
  10. Existing Light

    Existing Light Member

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  11. Chris Douglas

    Chris Douglas Member

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    The same but different

    I have had great success reversing plus x pan, but something you said threw me. I experimented with different exposure indexes, and had the best results shooting plus x at 500 ASA! Anything less resulted in progressively thinner positives. As for chemicals, I think I got the recipe from the darkroom cookbook. The first developer is D-76 1:1 with a smidge of sodium thiosulfate. The bleach is potassium dichromate and sulfuric acid, and the second developer is Dektol. I am at a loss to understand how 32 ASA will work. I wish I had a scanner so I could show how good these look. Unfortunately I will have to start again now that plus x is gone.

    Best regards,
    Chris
     
  12. Existing Light

    Existing Light Member

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    dunno what to tell you about the differences in exposure indexes we got :smile: . I wonder if the sodium thiosulfate and our different choices in first developer has anything to do with it?

    If I could scan mine, I'd post them. my projections look great, imho. Maybe if I ever get another projector or fix mine, I'll post photos of the projections. But then, I'd have to use the kind of camera that brings forth much buttrage among the users of these forums :D
     
  13. cinejerk

    cinejerk Member

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    I also have some black and white negative 16mm movie film. For some reason when I tried to use it as a reversal film the sensitivity was also greatly reduced.
    I tried some developed as a negative and asa was probably somewhere in the 50-75 range.
    When I tried to reverse it the asa was very low. I really couldn't measure it but probably less than 10.
    Anyway with a shutter speed around 60 I need about a f4 to get good reversals.
    Very strange. Usually people mention increase in sensitivity when doing reversals.
     
  14. Steve Roberts

    Steve Roberts Member

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    I've had some success rating FP4 at 25 ASA but was disappointed with my following roll that was far too dark and muddy ('moody' would have been OK!)
    Using Rodinal as first dev, permanganate bleach and Ilford Multigrade second dev.
    Steve
     
  15. Chris Douglas

    Chris Douglas Member

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    Its all good

    I'm impressed that others are experimenting with this. When I started out taking movies, I just developed them as negatives, and then printed an unexposed film by winding the film and the negative on a reel and running it through the camera pointed at a white surface. One of my friends' dad was a professional photographer who helped with film, tank, chemicals and advice. He said the negatives should be thin to get a good print. He was right, negatives that looked good for printing on paper made poor positives. I think this is the same rational for under exposing film for reversal. Thanks for starting this thread, it brought me back, as I was 12 when I was first doing this.
     
  16. cinejerk

    cinejerk Member

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    Thanks for the posts Steve and Chris. Yep, always wanted to be able to develop my own movie film. Now that digital is the norm I still want to work with film. I developed some super 8 E6 film back in the 80's.

    I have heard from many on this forum that for the best b&w positives you need a pretty active, contrasty first developer. D-19 with a touch of thoicyanate comes pretty close to that. I had bought a pouch of D-19 a while back and thought I would try it. When I opened the pouch I noticed the powder was quite brown. I just tossed that and made my own. I had all the chemicals laying around from my experimenting with E6 color process. The thiocyanate is suppose to help clear out the dmin good for projection.

    I have never tried the permanganate. I've heard it doesn't have very good shelf life. My chromate bleach has been good for over a year now.

    Wow Chris, you actually loaded a double thickness of film in your camera?
    That is an interesting solution to that problem.
    I like the reversal process in that is solves the negative and printing problem. Of coarse you only have the camera film to work with and the process can be a little touchy !!
     
  17. Ruadh495

    Ruadh495 Member

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    More reversals

    Hi,

    I've just picked up a film camera again and started reversal processing because I don't have a darkroom. I find reversal gives an increase in film speed. Using Kentmere film (it's cheap) the 100 gives decent results shot at 200.

    I add sodium thiosuphate pentahydrate (6g/ltr) to the first developer (Champion Suprol 1:9) and develop for 12min. Bleach is permanganate (1g/ltr) in 1% sulphuric acid. I bleach for 6min, clear for 2min (25g/ltr sodium metabisulphite), fog for 4min near a 20W CFT in room lighting (not daylight) and then second develop for 10min in Suprol 1:9 but without the thiosulphate. I fix (Champion AmFix 4min) after second development though it's probably unneccessary. 1:9 is the normal print strength for Suprol, 1:19 works well for negatives.

    I remove the film from the reel for fogging and I haven't found winding a wet film back on a problem, though loading a dry one on my ancient Paterson reel can be.

    Reversal does seem to soften the emulsion when wet, so I let the film dry entirely naturally rather than using a squeegee. I rely on muliple distilled water rinses to avoid water marks.

    I have also tried the Kentmere 400 in reversal, shooting at 800 and using the same process (including timings). It did work, but the contrast is a bit flat. I prefer the 100.

    Roy