Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,930   Posts: 1,585,340   Online: 1032
      
Page 2 of 5 FirstFirst 12345 LastLast
Results 11 to 20 of 47

Thread: AZO?

  1. #11

    Join Date
    Jun 2003
    Shooter
    Large Format
    Posts
    16,887
    max

    i think it was just a name.
    like dektol is a name, metol ( or kodak's name for their metol was elon )
    or selectol o r... i think azo was just a name, nothing more than that.
    like kodak is just a name, cause it sounded good, and was easy to remember.

    i could be wrong though...

  2. #12

    Join Date
    Jun 2006
    Shooter
    Multi Format
    Posts
    187
    It is catchy. I'd love to believe that's the case but I just don't believe they would use the name of an organic functional group without it having any relevance to the paper.

  3. #13
    ann
    ann is offline

    Join Date
    Sep 2002
    Shooter
    35mm
    Posts
    2,883
    Images
    26
    i know that Brovira has a high level of bromide but it was also full of cadmium so why not call it caovira.
    http://www.aclancyphotography.com

  4. #14

    Join Date
    Jun 2006
    Shooter
    Multi Format
    Posts
    187
    Quote Originally Posted by ann View Post
    i know that Brovira has a high level of bromide but it was also full of cadmium so why not call it caovira.
    Because cadmium was a staple of most papers for a long time. Would be like naming a paper silvira.

  5. #15
    ann
    ann is offline

    Join Date
    Sep 2002
    Shooter
    35mm
    Posts
    2,883
    Images
    26
    and bromide is in a lot of papers, but i surrender at this time.
    http://www.aclancyphotography.com

  6. #16
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,555
    Images
    65
    Velox, Velite and Azo were Kodak's trade names for slow gaslight or UV sensitive products that could be used under low room illumination. Azo had the best tone by far. Some early papers were stabilzed by using Sodium Azide which is explosive and hard to handle. Maybe this is where it came from. IDK.

    A derivative of Sodium Azide is used today in airbags in cars to puff them up when struck hard.

    Agfa produced a similar paper to Azo called Lupex. Azo and Lupex were both Chloro Iodide papers. That is, they were made with both chloride and iodide. I have argued this point before here, but it is true.

    Some eastern European companies still use Sodium Azide for stabilization of emulsions. See Jim Browning's web page for a formula which uses it.

    Kodabromide and Brovira were both Silver Chloro Bromide emulsions with a dash of iodide, a big slug of cadmium, some formulas had mercury and lead. They were a toxic brew depending on contrast grade and image tone. Cadmium was not used in Azo AFAIK.

    Cadmium was used in the make or just before coating and was used at about 5 - 15 grams for every 108 grams of silver which was a BIG dose. Current chemicals that replace Cadmium are used at about 6 x 10^-6 grams / 108 grams of silver, so even if they are a bit on the toxic side, they are used at levels of 10,000,000 x lower or thereabouts.

    Does this help?

    PE

  7. #17
    htmlguru4242's Avatar
    Join Date
    Aug 2005
    Location
    Sandy Hook, CT
    Shooter
    Multi Format
    Posts
    973
    On the topic of Azo and what it contains,

    PE, just out of interest, do you have any [relatively] specific information about Azo as to what it contained / how it was made?

  8. #18
    blaze-on's Avatar
    Join Date
    Nov 2004
    Location
    Riverside, CA
    Shooter
    Multi Format
    Posts
    1,432
    Images
    61
    Is there tri-x compound in tri-x film? or was it used for filming XXX movies?
    Matt's Photo Site
    "I invent nothing, I rediscover". Auguste Rodin

  9. #19
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,555
    Images
    65
    Azo was a single run silver chloro iodide. It was a very simple emulsion similar to the one I posted here by Bruce Kahn, formerly at RIT. It contained a stabilzer such as Tetra aza indene, and a sensitzing dye (IIRC - it may not have). It had no Cadmium in it AFAIK, but Kodabromide and other enlarging papers did.

    After the run, it had a very short digestion period and then was coated with muchochloric acid and formaldehyde hardeners. It had an overcoat applied at a second coating station. At one time, it used saponin as spreading agent, but Kodak was changing over, so I don't know if that was used in the later batches.

    The Agfa version used sodium sulfite and formalin only with a sulfonic acid spreading agent (again IIRC).

    Kodak Azo was coated on a tinted SW baryta support. At one time, Azo was supplied in 19 different paper surfaces. Samples are in the GEH archives and viewable by appointment.

    There was once a warm tone Azo which contained ammonium salts during the run, and also copper salts. This was similar to the Agfa Lupex.

    PE

  10. #20
    Vaughn's Avatar
    Join Date
    Dec 2006
    Location
    Humboldt Co.
    Shooter
    8x10 Format
    Posts
    4,765
    Images
    40
    Thanks, PE. Your willingness (and patience) to share info is much appreciated!

    Vaughn

Page 2 of 5 FirstFirst 12345 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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