Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 69,754   Posts: 1,515,937   Online: 986
      
Page 4 of 6 FirstFirst 123456 LastLast
Results 31 to 40 of 56
  1. #31
    Rudeofus's Avatar
    Join Date
    Aug 2009
    Shooter
    Medium Format
    Posts
    1,533
    Images
    10
    Quote Originally Posted by mr.datsun View Post
    I've had to put film processing on the back-burner for a while. I will need to try the C41 E6 bleach test but no idea how I can get a small enough amount for a test.
    You can possibly get a sample from some minilab near you, or you get one of these C41 or E6 kits. For this experiment it doesn't matter whether you use bleach or BLIX. If you let us know where "The end of the world" is, maybe some other APUG member nearby can give you a sample.
    Trying to be the best of whatever I am, even if what I am is no good.

  2. #32

    Join Date
    Oct 2008
    Location
    The End of the World
    Shooter
    Sub 35mm
    Posts
    242
    Images
    1
    Quote Originally Posted by Rudeofus View Post
    You can possibly get a sample from some minilab near you, or you get one of these C41 or E6 kits. For this experiment it doesn't matter whether you use bleach or BLIX. If you let us know where "The end of the world" is, maybe some other APUG member nearby can give you a sample.

    Rudeofus. Excellent idea.

    I'm in London within a stone's throw of the Arsenal stadium. If anyone could give me a sample it'd be very gratefully received.

  3. #33

    Join Date
    Oct 2004
    Location
    Near Tavistock, Devon, on the edge of Dartmoor.
    Shooter
    35mm
    Posts
    1,021
    What I'm using is the old-fashioned, traditional Sodium thiosulphate. Whether it's anhydrous or not - you've got me there! It's the only type I've ever come across - transparent crystals, elongated with several sides and up to a quarter inch in length, about an eighth diameter. My guess is that it's not anhydrous.

    I agree that the amount of hypo is a key factor - too much gives no true blacks and blown highlights, though rating the film at a higher ASA can give usable though low contrast results. When you say that you're using a fraction of the hypo I am perhaps I'm not explaining myself well. I'm dissolving 20g of hypo in 200cc H2O, then using 10cc of this solution per gramme hypo required. At 4g/litre, for my 35mm tank, which requires 300cc of solution to cover one film, I'm using 12cc or effectively 1.2g hypo. How much do you use?

    I'm not sure how much the last rinse inversions are necessary, but I guess I'm just erring on the side of caution.

    At a rough count-up, I've been through about ten films to get to where I am. Four were with Rodinal as first developer and were at best inconsistent. Then I latched on to the current process, starting with widely varying exposures (and ending up at box speed, as Ilford suggest), then playing with the first development time and hypo added. At one stage everything went to pot and I seemed to be back to square one but identified the problem as a fault with the shutter speeds on my Pentax K2 which, even in manual mode, were pretty much random! That's now away for repair.

    This evening I projected some reversal b/w slides to someone else for the first time and the reaction was one of surprise that they could be as effective and were more artistic than similar shots would be with all that distracting colour!

    Best wishes,

    Steve

  4. #34
    Rudeofus's Avatar
    Join Date
    Aug 2009
    Shooter
    Medium Format
    Posts
    1,533
    Images
    10
    Quote Originally Posted by Steve Roberts View Post
    What I'm using is the old-fashioned, traditional Sodium thiosulphate. Whether it's anhydrous or not - you've got me there! It's the only type I've ever come across - transparent crystals, elongated with several sides and up to a quarter inch in length, about an eighth diameter. My guess is that it's not anhydrous.
    You are correct, that's the pentahydrate Na2S2O3 * 5 H2O
    Trying to be the best of whatever I am, even if what I am is no good.

  5. #35

    Join Date
    Oct 2008
    Location
    The End of the World
    Shooter
    Sub 35mm
    Posts
    242
    Images
    1
    Quote Originally Posted by Steve Roberts View Post
    What I'm using is the old-fashioned, traditional Sodium thiosulphate. Whether it's anhydrous or not - you've got me there! It's the only type I've ever come across - transparent crystals, elongated with several sides and up to a quarter inch in length, about an eighth diameter. My guess is that it's not anhydrous.

    I agree that the amount of hypo is a key factor - too much gives no true blacks and blown highlights, though rating the film at a higher ASA can give usable though low contrast results. When you say that you're using a fraction of the hypo I am perhaps I'm not explaining myself well. I'm dissolving 20g of hypo in 200cc H2O, then using 10cc of this solution per gramme hypo required. At 4g/litre, for my 35mm tank, which requires 300cc of solution to cover one film, I'm using 12cc or effectively 1.2g hypo. How much do you use?

    Steve - you are explaining yourself well. I understood correctly.

    You are using 4g/L hypo.

    For Rodinal I'm using around 0.76g/L, for Dokumol I'm using around 2.88g/L

    You are using standard Sodium Thiosulphate (as confirmed by Rudeofus) whilst I'm using the anhydrous (which I now realise is the stronger of the two). Anhydrous is meant to be 1.6 times stronger by weight - and that largely explains the difference.

    I was interested that Rodinal seemed to require approx. 1/4 the hypo needed with Dokumol when I tried it.

    The fact that you have got where you are after 10 films is admirable!

  6. #36
    Rudeofus's Avatar
    Join Date
    Aug 2009
    Shooter
    Medium Format
    Posts
    1,533
    Images
    10
    Quote Originally Posted by mr.datsun View Post
    I was interested that Rodinal seemed to require approx. 1/4 the hypo needed with Dokumol when I tried it.
    Isn't Dokumol a much stronger and much faster developer? That would explain why it needs more solvent for the same (or at least similar) effect.
    Trying to be the best of whatever I am, even if what I am is no good.

  7. #37

    Join Date
    Oct 2008
    Location
    The End of the World
    Shooter
    Sub 35mm
    Posts
    242
    Images
    1
    Quote Originally Posted by Rudeofus View Post
    Isn't Dokumol a much stronger and much faster developer? That would explain why it needs more solvent for the same (or at least similar) effect.
    I speculated that for a given 1st developer, if less hypo was required to clear all the remaining undeveloped silver halides that prevent clear highlights, then that 1st developer must be converting more halides to silver. More action in the first developer = a lighter final positive image (and hence reduced need for the hypo).
    Last edited by mr.datsun; 06-04-2013 at 04:31 PM. Click to view previous post history.

  8. #38
    Rudeofus's Avatar
    Join Date
    Aug 2009
    Shooter
    Medium Format
    Posts
    1,533
    Images
    10
    There will always be some undevelopable silver halide that needs to be cleaned up by the solvent. The less time this solvent has for doing its job, the stronger it needs to be.
    Trying to be the best of whatever I am, even if what I am is no good.

  9. #39

    Join Date
    Oct 2004
    Location
    Near Tavistock, Devon, on the edge of Dartmoor.
    Shooter
    35mm
    Posts
    1,021
    Quote Originally Posted by mr.datsun View Post
    The fact that you have got where you are after 10 films is admirable!
    Not really - I did get off to a flying start, thanks to APUG and Ilford!

    Steve

  10. #40

    Join Date
    Oct 2008
    Location
    The End of the World
    Shooter
    Sub 35mm
    Posts
    242
    Images
    1
    Quote Originally Posted by Rudeofus View Post
    There will always be some undevelopable silver halide that needs to be cleaned up by the solvent.
    In theory could a developer develop the silver halides to max dMax at first run through?

    Quote Originally Posted by Rudeofus View Post
    The less time this solvent has for doing its job, the stronger it needs to be.
    I see your point, but in my case the R09 was used for 10 minutes and Dokumol for 12 minutes and the R09 needed less hypo.

    On a similar theme, will hypo reach an exhaustion point?

Page 4 of 6 FirstFirst 123456 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin