Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 68,696   Posts: 1,482,527   Online: 988
      
Page 2 of 18 FirstFirst 1234567812 ... LastLast
Results 11 to 20 of 171
  1. #11
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,710
    Images
    65
    The company is H. W. Sands, located in Florida.

    PE

  2. #12
    holmburgers's Avatar
    Join Date
    Aug 2009
    Location
    Rochester NY (native KS)
    Shooter
    Multi Format
    Posts
    4,400
    Images
    2
    Thanks for the depiction wildbill.

    Not knowing much about emulsion making yet, I'm surprised to hear that 3-separate emulsions are mixed. I guess I thought (somewhat naively) that the sensitizing nature would be applied equally to each grain. That is, a single theoretical grain would become sensitive to the full spectrum, as opposed to 3 grains from separate emulsions each "taking care of" a portion of the spectrum.
    If you are the big tree, we are the small axe

  3. #13
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,710
    Images
    65
    There are a variety of methods to achieve pan sensitization. Bill described a method I posted quite a while back for making Pan Matrix Film, but you can also get a panchromatic dye to do the job. Placing 3 dyes on one grain (or even 2) is rather difficult though.

    PE

  4. #14
    michaelbsc's Avatar
    Join Date
    Dec 2007
    Location
    South Carolina
    Shooter
    Multi Format
    Posts
    2,090
    Images
    5
    PE, this is the method you mentioned to me about a year ago to make Pan sensitive dry glass plates?

    MB
    Michael Batchelor
    Industrial Informatics, Inc.
    www.industrialinformatics.com

    The camera catches light. The photographer catches life.

  5. #15
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,710
    Images
    65
    Yes.

    PE

  6. #16

    Join Date
    Apr 2005
    Location
    San Bernardino, CA
    Shooter
    8x10 Format
    Posts
    732
    PE,
    Can you give some examples of panchromatic dyes ?
    I actualy tried,with one emulsion,adding both SDA3057(at 150mg/M Ag) and SDE3008(at 50mg/M Ag). It looked pritty good, as judged by a shot of the Kodak color chart. I went back to splitting batches though. Just to be on the safe side. Also, when using a split beam camera, I can actualy use a differntly sensitized emulsion behinde each of the color filters. I like that for several reasons.
    Bill

  7. #17
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,710
    Images
    65
    Bill;

    When you add 2 dyes to 1 emulsion, the more tightly adsorbed one can kick the other dye off the grain and you lose sensitivity in one region of the spectrum. That is why I suggest mixing 2 differently sensitized emulsions.

    As for a pan dye, well that is the problem. I have not yet found one commercially. We had them at EK. There is a problem with these too. Their spectral distribution may not match the spectrum you wish to capture, and it may vary from emulsion to emulsion. That is another reason I prefer the blending method. Of course this is only a problem with B&W materials. I've been fortunate that all of my work with spectral sensitization was in color where it was mandatory that a minimum of 3 emulsions be used. The B&W work was purely "theoretical" in meetings and such reviewing the work of the B&W people.

    PE

  8. #18
    holmburgers's Avatar
    Join Date
    Aug 2009
    Location
    Rochester NY (native KS)
    Shooter
    Multi Format
    Posts
    4,400
    Images
    2
    http://www.apug.org/forums/forum205/...vity-film.html

    Here is a very interesting discussion from about 5 years ago.

    I still haven't found the thread that everyone seems to be alluding to.
    If you are the big tree, we are the small axe

  9. #19

    Join Date
    Apr 2005
    Location
    San Bernardino, CA
    Shooter
    8x10 Format
    Posts
    732
    Yes,holmburers,
    The Search Engine on APUG is not very good.

  10. #20

    Join Date
    Apr 2005
    Location
    San Bernardino, CA
    Shooter
    8x10 Format
    Posts
    732
    I tried last night to find the elusive post,and could not. But it dose exist somewhere on this forum, of that I ame sure,
    Bill

Page 2 of 18 FirstFirst 1234567812 ... LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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