Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,274   Posts: 1,534,614   Online: 1086
      
Page 3 of 5 FirstFirst 12345 LastLast
Results 21 to 30 of 47

Thread: AZO?

  1. #21

    Join Date
    Oct 2003
    Location
    Richmond, VA
    Shooter
    Large Format
    Posts
    877
    Does PE stand for Photo Engineer or Photo Encyclopedia? You never cease to amaze me....

    Thanks for all you share with this community!
    John Bowen

  2. #22
    htmlguru4242's Avatar
    Join Date
    Aug 2005
    Location
    Sandy Hook, CT
    Shooter
    Multi Format
    Posts
    973
    Interesting to know, PE - I didn't realize it was so simple. Did the emulsion remain basically the same from its introduction right up until its demise?

  3. #23
    Curt's Avatar
    Join Date
    Sep 2005
    Location
    Pacific Northwest
    Shooter
    Multi Format
    Posts
    4,545
    Images
    15
    Are there any Rodents in Rodinal?

    If PE doesn't know, it isn't worth knowing.
    Everytime I find a film or paper that I like, they discontinue it. - Paul Strand - Aperture monograph on Strand

  4. #24
    TheFlyingCamera's Avatar
    Join Date
    May 2005
    Location
    Washington DC
    Shooter
    Large Format
    Posts
    8,310
    Blog Entries
    51
    Images
    434
    if not rodents, then perhaps rhododendrons oh, wait, that would be rhodinal

  5. #25
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,972
    Images
    65
    Azo and all of the other emulsions varied quite a bit from their very first incarnations. They evolved over the years as gelatin changed, support changed and etc.

    For example, one product could not be made with the same image tone when Cadmium was removed. It therefore had to be discontinued. I forget the product, but it was either Opal, Medalist or one of those era emulsions.

    A major change in all papers took place when the active gelatins were no longer used. All papers were reformulated to use sodium thiosulfate at about 100 mg/mole of silver (108 grams). Silver Chlorides were one of the most difficult to convert and were the last to use active gelatins. In fact, sulfur + gold sensitization on AgCl was active as a big project when I joined Kodak, as it was desirable to make a high speed fine grained print film for motion picture. A few papers could not be reformulated properly for use with inert gelatins and this led to their being discontinued.

    Ektacolor 20 was discontinued due to Cadmium at about 15 grams / mole and a Mercury salt at about 0.1 gram / mole. It was reformulated with organic compounds to give the same curve, higher speed and fixed speed from batch to batch with 2x the development rate. This was not applied to B&W papers as they could not adjust the already short development times for the single layer materials, but eventually it evolved into the modern papers which develop to completion.

    Azo remained virtually the simplest formula Kodak produced, but papers such as Kodabromide were quite complex by comparison.

    For the Ilford, Agfa and Fuji guys reading this (and some of my other posts - or maybe even some of the Kodak guys), I'm drastically simplifying things and also not disclosing everything to avoid disclosure of confidential data in public.

    Oh, there are no rodents in Rodinol. But, there are some rodents living under my front porch. I've tried alum and it chased them off for a while but they finally decided that they could stand the pucker power of alum and dug through it again today twice. I may try HQ to see what develops.

    PE

  6. #26
    athanasius80's Avatar
    Join Date
    Dec 2004
    Location
    Huntington Beach, California
    Shooter
    Multi Format
    Posts
    639
    Images
    15
    FYI, Azo wasn't even a Kodak invention. It was brought out by the Photo Materials Co. in 1898. EKC bought out Photo Materials in July of that year producing PMC Bromide until (I think) the 1930s, and Azo until... well you know that part already.

    C.

  7. #27
    Curt's Avatar
    Join Date
    Sep 2005
    Location
    Pacific Northwest
    Shooter
    Multi Format
    Posts
    4,545
    Images
    15
    I like that name, "Photo Materials Co.", they said it better back then.
    Everytime I find a film or paper that I like, they discontinue it. - Paul Strand - Aperture monograph on Strand

  8. #28
    Gustavo_Castilla's Avatar
    Join Date
    Sep 2004
    Location
    Bryan Texas
    Shooter
    Large Format
    Posts
    890
    Images
    143
    Here is the answer.
    Simple as Azo was and is a properatyry name of Kodak other then Silver chloride.
    NO ONE really knows what is on the paper hence no copycats no matter what anybody tells you and nobody really knows .
    want to know more go to the getty web site and go to the research deportment and look it up there
    Gustavo Castilla
    We are not moved by things ,
    but by the views we take of them.
    Epictitus.
    My site
    My flicker page
    Facebook
    Contact

  9. #29
    Jim Fitzgerald's Avatar
    Join Date
    Aug 2005
    Location
    Ventura, Ca
    Shooter
    ULarge Format
    Posts
    1,778
    Images
    107
    Quote Originally Posted by Curt View Post
    Are there any Rodents in Rodinal?

    If PE doesn't know, it isn't worth knowing.
    Curt,You are killing me with this one!!! I can't stop laughing!!! I'm having a hard time typing. Just what I needed after a brutal day at work. Thanks.

    Jim

    Oh, by the way was Polymax before or after Mad Max??

  10. #30
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,972
    Images
    65
    Quote Originally Posted by Gustavo_Castilla View Post
    Here is the answer.
    Simple as Azo was and is a properatyry name of Kodak other then Silver chloride.
    NO ONE really knows what is on the paper hence no copycats no matter what anybody tells you and nobody really knows .
    want to know more go to the getty web site and go to the research deportment and look it up there
    Gustavo;

    No one? Really? Kodak and Agfa had almost identical products which were both Chloroiodide contact papers. IDK about you, but I've been able to recreate it from what I know about Kodak emulsions. I can also recreate Lupex, the Agfa equivalent. They are so close it is amazing, really.

    PE

Page 3 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