Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,549   Posts: 1,544,641   Online: 786
      
Results 1 to 7 of 7
  1. #1
    htmlguru4242's Avatar
    Join Date
    Aug 2005
    Location
    Sandy Hook, CT
    Shooter
    Multi Format
    Posts
    973

    RA-4 Processing from somewhat unstandard chemicals

    I'm looking to process some RA-4 paper, both for prints from color negatives and for use with in-camera negatives.

    A full RA-4 processing kit is quite expensive, so I was looking to put together a "kit" from more chemicals that I have around the house. I'll buy the Color developer, which is not too expensive. I know that standard fixer can be used, though it takes a little longer and gets depleted much faster.; so that's out. I also do not have a need for longevity at this point, as I am just experimenting, so that eliminates the need for stabilizer. For bleach I was thinking about using Iodine, as it seems to work for bleaching silver from standard B&W prints.

    Would this work at all, or am I completely off base?

  2. #2

    Join Date
    Nov 2004
    Location
    Italia
    Shooter
    Multi Format
    Posts
    4,680
    On the fixer colour fixer tends to be cheaper then B&W .

    The kits tend to be more expensive because of size and packaging. If you get bigger sizes the costs drop. Just comparing the JD kit the bigger kits are much cheaper then the 1 litre.

    If you buy the fix and bleach in bigger bottles and the developer in smaller sizes you'll have the cost savings from bigger sizes and not have to worry about the developer going off.

  3. #3
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,026
    Images
    65
    Yes, you are off base.

    The pH of the fix is critical, and the type of bleach is critical. The iodine will probably destroy part if not most of the dyes.

    PE

  4. #4

    Join Date
    Aug 2005
    Location
    Los Alamos, NM
    Shooter
    Multi Format
    Posts
    2,052
    PE: Could a separate ferricyanide or permanganate bleach be used with RA-4?

  5. #5
    htmlguru4242's Avatar
    Join Date
    Aug 2005
    Location
    Sandy Hook, CT
    Shooter
    Multi Format
    Posts
    973
    I've placed color prints in iodine (after they've been fixed / stabilized), and there was no effect whatsoever ...

  6. #6
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,026
    Images
    65
    Quote Originally Posted by htmlguru4242
    I've placed color prints in iodine (after they've been fixed / stabilized), and there was no effect whatsoever ...
    IDK then. Maybe they will survive, but was the iodine strong enough to bleach silver? If it was not at the proper strength or pH, then it would be weaker than you would use in practice. In my experience, iodine destroyed the older dye set by reacting with them.

    Ferricyanide would work in the following sequence:

    Prewet
    Developer
    stop (acetic acid + sulfite - this is also a clearing bath)
    wash
    bleach (rehalogenizing ferricyanide)
    fix (pH cannot be lower than about 6.2 and cannot have hardener)
    wash

    I cannot predict the effects on dyes (hue or bandwidth) or dye stability.

    PE

  7. #7
    htmlguru4242's Avatar
    Join Date
    Aug 2005
    Location
    Sandy Hook, CT
    Shooter
    Multi Format
    Posts
    973
    The ferrycyanide bleach somds good... And, yes, the iodine (4% tincture) is more than strong enough to completely bleach silver. At the strength that I have pre-mixed, with B&W paper, it will fully bleach a completely black print in about 2 to 3 minutes, to a yellow color. Up on immersion in fixer, it turns paper base white ...

    I'll check the pH of my non-hardening fixer; it may work ...



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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