Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,536   Posts: 1,544,245   Online: 737
      
Page 3 of 4 FirstFirst 1234 LastLast
Results 21 to 30 of 35

Thread: ASA developer

  1. #21
    Bruce Osgood's Avatar
    Join Date
    Sep 2002
    Location
    Brooklyn, N.Y. USA
    Shooter
    Multi Format
    Posts
    2,434
    Images
    45
    [QUOTE=Harold33;1553849]You are certainly right. But I'm curious to see the formula.



    If you could find them, I would be gratefull.[/QUOTE
    ---------------------------------------------------------------

    Ian had sent me the following formula for Adox Borax MQ developer a couple of years ago.

    Name: Adox Borax MQ


    Use/Discription: Prefered over D-76
    Additional recommendation: Dilute 1 + 1.5

    Mixing Order To make:1 Liter or
    Distilled Water 52-c To Make: 750 mL
    Metol 2.00 g
    Sodium Sulphite (anhyd) 80.00 g
    Hyudroquione 4.00 g
    Borax 4.00 g
    Potassium Bromide 0.50 g

    Water to make Liter 1000.00 mL
    Dev times are 10-20% longer, but there is a touch more speed 1.3 to 1/2 a stop. Ian
    ---------------------------------------------------------------------------------------------

  2. #22
    Bill Burk's Avatar
    Join Date
    Feb 2010
    Shooter
    4x5 Format
    Posts
    3,280
    Images
    46
    Quote Originally Posted by Stephen Benskin View Post
    This is the formula from ANSI PH2.5 - 1979.

    Attachment 75120

    BTW, I'd like to see someone substantiate the 1/3 stop speed statement. Let's try to support statements with facts and help reduce the propagation of myths and hearsay.
    I guess I've got my shopping list then...

  3. #23

    Join Date
    Jul 2010
    Location
    Southern USA
    Shooter
    Multi Format
    Posts
    3,834
    I sense all the "testanistas" salivating new that the formula has be disclosed.
    Last edited by Gerald C Koch; 10-04-2013 at 12:05 AM. Click to view previous post history.
    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. #24

    Join Date
    Jun 2012
    Location
    UK
    Shooter
    Multi Format
    Posts
    1,400
    monomethyl p-aminophenol sulfate is what the rest of us call Metol - have I understood that correctly?

  5. #25
    Ian Grant's Avatar
    Join Date
    Aug 2004
    Location
    West Midlands, UK, and Turkey
    Shooter
    Multi Format
    Posts
    16,270
    Images
    148
    It's generally forgotten that many years ago, when the ASA system came into existence, roll films, sheet films and plates were routinely developed in faster working and more contrasty developers like D61a, D163 (UK), D72 (US) rather than D76, Adox Borax MQ etc. So it's no co-incidence that the developer Steven Benskin posted from 1943 is close to diluted (roughly 1+1) D61a.

    It was my understanding that Adox Borax MQ was very closely related to the ASA developer for "Miniature" films, and the formula Steven posted says it's for testing Roll film & film packs.

    Somewhere I have an article (probably in a book) discussing the merits of the ASA & DIN testing methods and listing both formulae.

    Ian

  6. #26

    Join Date
    Jul 2010
    Location
    Southern USA
    Shooter
    Multi Format
    Posts
    3,834
    Quote Originally Posted by pdeeh View Post
    monomethyl p-aminophenol sulfate is what the rest of us call Metol - have I understood that correctly?
    Yes you did, the name is the correct chemical name for Metol or Elon.
    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

  7. #27

    Join Date
    Jan 2012
    Shooter
    Multi Format
    Posts
    62
    Quote Originally Posted by Ian Grant View Post
    My notes say the ASA developer was the same as Adox Borax MQ, however there may have been a slight variation due to weight conversions. (numbers getting rounded up or down.
    It's true that Adox MQ was used (among others) to control the speed of films. But it's not the same than the ASA dev.
    According to Anchell & Troop, FDC , 42, the ASA included carbonate and bicarbonate as buffer.

  8. #28
    Ian Grant's Avatar
    Join Date
    Aug 2004
    Location
    West Midlands, UK, and Turkey
    Shooter
    Multi Format
    Posts
    16,270
    Images
    148
    Quote Originally Posted by Harold33 View Post
    It's true that Adox MQ was used (among others) to control the speed of films. But it's not the same than ASA dev. According to Anchell & Troop, FDC , 42, the buffer included carbonate and bicarbonate.
    True but not the one for miniature films.

    Ian

  9. #29

    Join Date
    Jan 2012
    Shooter
    Multi Format
    Posts
    62
    Quote Originally Posted by Stephen Benskin View Post
    This is the formula from ANSI PH2.5 - 1979.

    Attachment 75120
    .
    I think this is the right one with the carbonate+bicarbonate buffer.
    The pH (10,1) is quite high !

  10. #30
    Stephen Benskin's Avatar
    Join Date
    Jan 2005
    Location
    Los Angeles
    Shooter
    4x5 Format
    Posts
    1,218
    The origins of the 1/3 stop meme may have come from the Forward of the standard. It's in the 1979 version and may be in the earlier versions. "(3) For any specific developer, the sensitometric speed rating method of this standard includes a 1/3 stop underexposure safety factor." This refers to where the average shadow exposure falls in relation to the fractional gradient point and is explained in the paper Safety Factors in Camera Exposure.

Page 3 of 4 FirstFirst 1234 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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