Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,571   Posts: 1,545,505   Online: 1223
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 13
  1. #1

    Join Date
    Jun 2009
    Location
    Odessa, UA
    Shooter
    35mm
    Posts
    234

    Ilfotec DD-X formula?

    Hello

    I found Ilford patent US5210010 with PQ formula very similar to MSDS DD-X. Also this formula have same dilution and pH as DD-X. What do you think about this?

    Potassium Sulphite 65% 548ml
    Water 380ml
    Glycol 45ml
    Hydroquinone 44g
    Phenidone 1.2g
    Borax 23.5g
    DAPTA 4.8g

    dilute 1+4, pH=8.5

  2. #2
    Rudeofus's Avatar
    Join Date
    Aug 2009
    Shooter
    Medium Format
    Posts
    1,653
    Images
    10
    If you look at the MSDS, Ilford seems to use DTPA instead of DAPTA in their product. Which is good because DTPA is much easier to get and cheaper ...
    Trying to be the best of whatever I am, even if what I am is no good.

  3. #3

    Join Date
    Jul 2010
    Location
    Southern USA
    Shooter
    Multi Format
    Posts
    3,844
    There is no guarantee that this formula is anything like DD-X. Patents often contain such formulas as proof of a particular concept. Companies may try various methods of obfuscation and may even leave out important ingredients.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  4. #4

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    4,756
    My understanding is DDX is buffered (Borax-Boric acid).

  5. #5

    Join Date
    Apr 2008
    Location
    Escondido, California, USA
    Shooter
    35mm RF
    Posts
    656
    Quote Originally Posted by Michael R 1974 View Post
    My understanding is DDX is buffered (Borax-Boric acid).
    Due to an obscure fact of chemistry, it turns out that the formula posted by Relayer is buffered, because Borax itself is buffered. When mixed into water, Borax forms the equivalent of Boric acid, thus becoming its own buffer. So Borax is self-buffering. That's why Borax is often used to calibrate pH-meters. Now, whether that formula is close to DD-X is anyone's guess.

    EDIT 1: Rudeofus prefers DTPA. Interestingly, the patent says "The preferred sequestering agent is [...] DTPA." So why didn't they use it in their sample formula?

    EDIT 2: Looking into this some more, I see that the MSDS for DD-X specifies (1) Boric acid (Michael R mentioned this), (2) Dimezone S instead of Phenidone, and (3) DTPA instead of DAPTA. So I'd say the patent was for an early formula which the engineers improved later. Based on quantity-ranges in the MSDS, I'd say this is similar to DD-X. Given this patent-formula and the MSDS, it wouldn't be hard to reverse engineer the present formula. Anyone want to try it?

    Mark Overton
    Last edited by albada; 03-25-2013 at 01:04 AM. Click to view previous post history.

  6. #6

    Join Date
    Jun 2009
    Location
    Odessa, UA
    Shooter
    35mm
    Posts
    234
    Sequestering agent isn't so important part of formula from patent. More interesting that developer omit any antifoggant (KBr, BZT etc)

    working solution 1+4 must be like to next:

    Potassium Sulphite 71g
    Hydroquinone 8.8g
    Phenidone 0.25g
    Borax 4.7g

    71g of Potassium Sulphite = 71/MW(K2SO3) = 71/156.26 = 0.4544M = 0.4544*MW(Na2SO3) = 0.4544*126.04 = 57.3g of Sodium Sulphite
    Last edited by Relayer; 03-25-2013 at 03:03 AM. Click to view previous post history.

  7. #7
    Ian Grant's Avatar
    Join Date
    Aug 2004
    Location
    West Midlands, UK, and Turkey
    Shooter
    Multi Format
    Posts
    16,276
    Images
    148
    Quote Originally Posted by albada View Post

    EDIT 2: Looking into this some more, I see that the MSDS for DD-X specifies (1) Boric acid (Michael R mentioned this), (2) Dimezone S instead of Phenidone, and (3) DTPA instead of DAPTA. So I'd say the patent was for an early formula which the engineers improved later. Based on quantity-ranges in the MSDS, I'd say this is similar to DD-X. Given this patent-formula and the MSDS, it wouldn't be hard to reverse engineer the present formula. Anyone want to try it?

    Mark Overton
    The switch from Phenidone to Dimezon S in Ilford liquid developers seems to co-incide with the change in sub-contractors producing Ilfords chemistry.

    Older MSDS data for these developers is very much more informative, they show that Phenidone was used originally in DDX.

    Ian

  8. #8
    Rudeofus's Avatar
    Join Date
    Aug 2009
    Shooter
    Medium Format
    Posts
    1,653
    Images
    10
    Quote Originally Posted by Relayer View Post
    Sequestering agent isn't so important part of formula from patent. More interesting that developer omit any antifoggant (KBr, BZT etc)
    Be careful with that statement. Most common sequestering agents buffer in the pH range and DTPA is no exception (see page 6). Choosing a different sequestering agent can give you a different pH and buffer strength! Also note that the patent lists DTPA, while the MSDS lists DTPA pentasodium salt, the first one is a strong acid while the latter one is caustic (and much easier to dissolve). If pH is suitably chosen there is a good chance that no restrainer is needed.
    Trying to be the best of whatever I am, even if what I am is no good.

  9. #9

    Join Date
    Jun 2009
    Location
    Odessa, UA
    Shooter
    35mm
    Posts
    234
    Quote Originally Posted by Rudeofus View Post
    Be careful with that statement. Most common sequestering agents buffer in the pH range and DTPA is no exception (see page 6). Choosing a different sequestering agent can give you a different pH and buffer strength! Also note that the patent lists DTPA, while the MSDS lists DTPA pentasodium salt, the first one is a strong acid while the latter one is caustic (and much easier to dissolve). If pH is suitably chosen there is a good chance that no restrainer is needed.
    Yes, you right. If we omit DTPA or change it to other agent we need correct (decrease) amount of borax for required pH=8.5. This isn't a provlem

  10. #10
    Rudeofus's Avatar
    Join Date
    Aug 2009
    Shooter
    Medium Format
    Posts
    1,653
    Images
    10
    Quote Originally Posted by Relayer View Post
    Yes, you right. If we omit DTPA or change it to other agent we need correct (decrease) amount of borax for required pH=8.5. This isn't a provlem
    It's not only about pH, it's also about buffer strength! DTPA is a buffer at pH 8.5, if if we use less Borax in order to compensate for omission of DTPA, we create a much weaklier buffered developer.
    Trying to be the best of whatever I am, even if what I am is no good.

Page 1 of 2 12 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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