Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,560   Posts: 1,545,261   Online: 813
      
Page 28 of 32 FirstFirst ... 182223242526272829303132 LastLast
Results 271 to 280 of 317
  1. #1
    Ian Grant's Avatar
    Join Date
    Aug 2004
    Location
    West Midlands, UK, and Turkey
    Shooter
    Multi Format
    Posts
    16,273
    Images
    148

    Modern Rodinal Substitutes Part II

    Apologies for having to start a new thread but I can't read or even access the first to reply to posts.

    So with a bit of telepathy

    Quote Originally Posted by Kirk Keyes View Post
    Well, there's a problem there, as it's really hard to measure pH accurately when it gets much above 12.5 or so. You have to start getting special electrodes and the like.

    But for MSDS work, it doesn't have to be too precise.
    __________________
    Kirk

    A point that's being missed is that A&O give a figure of 2.7% Potassium Hydroxide not 3% in older Agfa MSDS.

    The pH is around 14 sure, but the actual requirement is the pH of the working dilute solution rather than the concentrate which is given elsewhere as pH 11.55, which I commented on in the first post of the thread.

    Way back Ron (PE) mentioned adjustments to Rodinal before bottling, the question we need to ask is are they adjusting on the basis of the concentrate, or also doing some tests on a dilute sample, as this will be a far more accurate indicator.

    Can someone please post a link to this continuation on the original post.

    Ian

  2. #271
    Ian Grant's Avatar
    Join Date
    Aug 2004
    Location
    West Midlands, UK, and Turkey
    Shooter
    Multi Format
    Posts
    16,273
    Images
    148
    Probably making old style Rodinal with Ascorbic might work, Sulpite & just enough KOH to convert the p-Aminophenol but no more, if it starts at pH 11.8 it may drop enough on dilution to 1+50. The sulphite itself is a powerful anti-oxidant and that's almost certainly why it's at such a high level compared to other developers.

    Ian

  3. #272
    gainer's Avatar
    Join Date
    Sep 2002
    Posts
    3,726
    Images
    2
    You will be happy to find out that the experiment failed when I tried to bring the concentrations of p-aminophenol and ascorbic acid up to the level we're looking for in a concentrated stock. The only real difference is the substitution of about 29 grams of potassium ascorbate for 192 grams of potassium sulphite in 500 ml. What am I missing?
    Gadget Gainer

  4. #273
    Ian Grant's Avatar
    Join Date
    Aug 2004
    Location
    West Midlands, UK, and Turkey
    Shooter
    Multi Format
    Posts
    16,273
    Images
    148
    Is tooooooooooo late at night

    Well here in Turkey anyway

    I'll look tomorrow if I'm not out doing the rounds with the Crown Graphic . . . . . . . . . . .

    Ian

  5. #274

    Join Date
    Jul 2008
    Location
    Voronezh, Russia
    Shooter
    35mm
    Posts
    26
    Quote Originally Posted by Ian Grant View Post
    Looking at the Sodium Benzenesulfonate further it's use is given in at least 4 Fuji Patents as an anti-oxidant, alongside other examples such as Suphites or Metabisulphites themselves and Ascorbic acid. It's also used in photothermography by some US companies..

    If Agfa did or do still use it then it's possible that anyone trying to analyse Rodinal might think Sodium Benzesulfonate or another similar anti-oxidant was an unidentifiable fevloping agent. Ilford patented some anti-oxidants in the 1950's presumably for use in Ilfosol originally a Phenidone/Glycin based developer, and these can also be used to form developing agents. (4-aryl-2-oxytetronimic acids).

    So thanks that's useful information.

    Ian
    I'm not sure that sodium benzenesolfonate came from Agfa - the book states it was proposed by one of russian scientists as an agent preventing oxigen diffusion into the stock solution of Rodinal. It was stressed about diffusion, but not oxidation. And for me this makes the point - if there is no diffusion, there is no oxidation. But from practice it is also an anti-oxidant.

    I mixed two batches with benzenesolfonate and without and there is huge difference:
    1. First batch was without it, and when I got right NaOH content, I've added water to make 1 liter. It was light in color before water, and became much darken when I added. Obviously, water contained a lot of oxigen, which oxidized pAP, and I had color change.
    2. Second batch - I added benzensulfonate, and after adding the water to make 1 liter, there is no color change.
    One of my friends told me that he noted shelf life difference for rodinal made with benzenesolfonate and without from his previuos experience.

  6. #275
    Ian Grant's Avatar
    Join Date
    Aug 2004
    Location
    West Midlands, UK, and Turkey
    Shooter
    Multi Format
    Posts
    16,273
    Images
    148
    Thanks for that clarification. You seemed to imply it came from Foma 's R09 formula before. Agfa/Bayer actually manufacture the chemical and it has other uses, but it's significant that Fuji use it as an anti-oxidant in one of their Instant film patents.

    It makes sense to use an anti-oxidant, the problem is the high pH makes choice more difficult.

    Ian

  7. #276
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,033
    Images
    65
    I have found no reference in my notes about sulfonic acids as antioxidants, but I have found notes about sulfinic acids being used as antioxidants. I have no mention in those notes what types of sulfinic acids. I have only conducted a very simple google search so far. So, I have no more to add.

    PE

  8. #277

    Join Date
    Jun 2004
    Location
    Portland, OR
    Shooter
    4x5 Format
    Posts
    3,268
    Sulfonic acids, as a class, are often used as detergents/wetting agents. Benzene sulfonic acid is probably not used for that much as it's rather reactive, I thought. But longer chained sulfonic acids are, as you can have an alkane or aromatic on an alkane chain and the sulfonic acid group on the other end, and that's good for detergents.
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  9. #278
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,033
    Images
    65
    The classic detergent or surfactant of that class is di-nonyl-napthalene sulfonic acid sodium salt. Yes, I agree Kirk, they seem to be detergents, but then Sorbitol is a sugar but can act as an oxygen barrier by eating up free radical oxygen, so I don't rule this possible use out.

    PE

  10. #279
    Ian Grant's Avatar
    Join Date
    Aug 2004
    Location
    West Midlands, UK, and Turkey
    Shooter
    Multi Format
    Posts
    16,273
    Images
    148
    It appears that I had the Orwo R09 formula sat on my laptop from 2 years ago, and misplaced it but couldn't translate "Benzosulifinian sodowy" from the Polish.

    So the question is are Sodium benzenesulfonate and Benzosulifinian sodowy the same. The compound is in Patent's for a medical thermal imaging films as an anti oxidant, one made by a Rochester based company (not Kodak).

    In general anti-oxidants are rare in B&W developers - except Champlin's formulae, the high sulphite level rules out many that are used in Colour developers.

    Ian

  11. #280
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,033
    Images
    65
    Grant;

    AFAIK, Benzenesulfinian is Benzene sulfinic not sulfonic which would be -sulfonian or somehing like tht. Polish speakers please verify my very rusty translating efforts of organic chemistry.

    An afterthought: We might ask pavel if he can verify that his Russian translation is benzene sulfonic..... That might also be questioned in view of my notes on Sulfinic acids.

    PE
    Last edited by Photo Engineer; 10-04-2009 at 03:53 PM. Click to view previous post history. Reason: Added afterthought



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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