Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 68,713   Posts: 1,483,017   Online: 672
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 14
  1. #1

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    4,265

    D-512 compensating developer (Silom Horwitz)

    This formula appears in Modern Photographic Processing (Grant Haist) Vol. 1. in the context of low contrast development. The formula is attributed to Silom Horwitz (1967), based on Marilyn Levy's studies of the superadditivity of Phenidone and Pyrogallol.

    Stock solution (1L):

    1g Calgon
    40g Sodium Sulfite
    6g Pyrogallol
    2g Phenidone

    The working solution is a 1+1 dilution of the above stock solution. Development time at 68F was 10min for Kodak Plus-X, rated at ISO speed. It was recommended only for high contrast subjects requiring low contrast development.

    I suspect the Calgon could be eliminated if distilled water is used for mixing/dilution.

    This has been on my list for a while in my ongoing "survey" of purported low gamma and high speed/low gamma developers. I'm curious to try it, although dissolving 2g Phenidone is a pain. Perhaps I'll mix the working solution (halving all amounts) as a one-shot.

    If anyone out there has already tried Horwitz D-512 with any current films I'd be curious to hear about it.

    Michael

  2. #2
    Rudeofus's Avatar
    Join Date
    Aug 2009
    Shooter
    Medium Format
    Posts
    1,425
    Images
    10
    I have not tried this one but mixed several other low contrast developers (POTA, Delagi 8) which need similar amounts (1-2 g/l) of Phenidone in solution. Common sources recommend using hot water to start, this is why Calgon + hot tap water is better than DI water which you need to heat separately. I was able to dissolve 50 g/l Phenidone in Propyleneglycol (or supposedly even better: Diethyleneglycol) and use this stock solution to put the required amount of Phenidone into cold water quickly. It's not cheap but worth the effort, and I don't use such a dev on a daily basis anyway.

    For all those who care: low contrast devs give amazing results with night time exposures on Delta 3200 if they include strong highlights. The low contrast aspect of these devs compensates nicely for the usually high contrast of these scenes (which is even more increased by the Scharzschild effect) and thereby in combination creates beautiful and very realistic looking images that can be easily printed with grades 2-4.
    Trying to be the best of whatever I am, even if what I am is no good.

  3. #3
    Ian Grant's Avatar
    Join Date
    Aug 2004
    Location
    West Midlands, UK, and Turkey
    Shooter
    Multi Format
    Posts
    15,954
    Images
    148
    Ilford published a Phenidone - Pyrogallol variation of their ID-4 developer formulae in the original 1941 Kendall Phenidone Patent:

    [SIZE=4]Example 3[/SIZE]


    Part A
    Phenidone 0.4 gm.
    Potassium Metabisulphite 12 gm.
    Pyrogallol 12 gm.
    Water to make 1 litre


    Part B
    Sodium carbonate (anhyd.) 75 gm.
    Water to make 1 litre


    To use 1 Part A + 1 Part B
    Similar in use to a Developer containing 4 gms of Metol



    Obviously quite different to D-512 which has a far higher proportion of Phenidone needed for a balanced Super-Additive effect, Pyrogallol was also used in developers as an oxygen scavenger.

    Ian

  4. #4
    Rudeofus's Avatar
    Join Date
    Aug 2009
    Shooter
    Medium Format
    Posts
    1,425
    Images
    10
    Quote Originally Posted by Ian Grant View Post
    Obviously quite different to D-512 which has a far higher proportion of Phenidone needed for a balanced Super-Additive effect, Pyrogallol was also used in developers as an oxygen scavenger.
    The biggest difference between ID-4 and D-512 is not so much the different amount of Phenidone but the extra Carbonate that ID-4 adds. That extra Carbonate brings pH way up and likely changes the overall properties of this dev quite a bit. D-512 is very close to POTA ...
    Trying to be the best of whatever I am, even if what I am is no good.

  5. #5

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    4,265
    Indeed it seems to be a more "stabilized" version of POTA. In Anchell/Troop the addition of Pyro, HQ or Catechol are discussed as potential ways of stabilizing the Phenidone enough (by superadditivity) to make POTA easier to use. Even Metol is considered (not sure why but it seems to follow Crawley's thoughts) and also Glycin - presumably for its apparent ability to make other agents more resistant to oxidation. But the suggested formulas in FDC use small amounts of these additional agents, less sulfite and sometimes additional alkali. D-512 seems quite different in its Pyro concentration.

    On the other hand the formulas in FDC are intended primarily for document/microfilms. D-512 is mentioned in Haist in the context of compensating developers for general purpose films, while POTA is discussed in the context of microfilm development.

  6. #6

    Join Date
    Nov 2004
    Posts
    1,091
    Here is the working solution of H&W Control (microfilm developer):
    Sodium Sulfite......................4.28g
    Hydroquinone.......................0.076g
    Phenidone............................0.52g
    Sodium Carbonate.................2.19g
    Water to...............................1L

    So D-512 does have a much higher concentration of the secondary developer that regenerates Phenidone.
    Perhaps this is to remove more of the oxidized phenidone that would otherwise give a flat image with ordinary film:
    http://www.jackspcs.com/wondphen.htm

  7. #7

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    4,265
    H&W Control is another one I've always wanted to try with general purpose film (not microfilm) to see if decent speed can be maintained with extreme low contrast.

    Alan, is this the actual formula or an approximation from a patent?

    It would clearly operate at a much higher pH than D-512, and with its lower sulfite content and very small concentration of secondary agent, it resembles the various experimental formulas propsed in FDC as modifications to POTA where the addition of a small amount of a secondary superadditive agent allows for a lower concentration of Phenidone (and less sulfite).

    What I always find funny are formulas in which weight quantities are given with precision to hundredths (or even thousandths!?) of a gram.

  8. #8

    Join Date
    Nov 2004
    Posts
    1,091
    I have only used H&W Control developer with microfilms,by reducing the time even the contrasty Adox CMS 20 could be developed in it.
    The EI obtained is good, but not up to that obtained using the dedicated developers from Spur.For conventional film one could try developing for a long time to see if it would build contrast.
    The formula I gave above derives from that given for 2.1L of working solution here:
    http://www.frugalphotographer.com/in...ry-general.htm
    The phenidone is easy to dissolve in 70% isopropyl alcohol from a pharmacy.

  9. #9

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    4,265
    Ah... I should have remembered H&W Control is made as a 132ml concentrate diluted to 2.1L - hence the decimals everywhere when converted to a per-liter basis.

    I'm adding it to my list of things to try. Thanks.

  10. #10
    Regular Rod's Avatar
    Join Date
    Aug 2012
    Location
    Derbyshire
    Shooter
    Medium Format
    Posts
    327
    Is the Calgon not there to provide an alkali? How long does the stock solution keep for?

    RR

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