How color film actually looks

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by Photo Engineer, Feb 28, 2007.

  1. Photo Engineer

    Photo Engineer Subscriber

    Messages:
    25,773
    Joined:
    Apr 19, 2005
    Location:
    Rochester, NY
    Shooter:
    Multi Format
    Here are photo micrographs of actual color films.

    One compares film to a human hair, and the other shows film before and after processing.

    In the before and after process photos, you can see the silver grains in one and not in the other, and you can also see the change in the layers.

    Again, I am indebted to my friend, Dr. Bruce Kahn for permission to use these photos.

    You can see from the size of the hair in comparison to the thickness of the film layers why I have likened photo engineering to designing a biological system, as we are working on the scale of cellular structures or smaller, when we build and examine film.

    PE
     

    Attached Files:

  2. JBrunner

    JBrunner Moderator Staff Member Moderator

    Messages:
    7,075
    Joined:
    Dec 14, 2005
    Location:
    Basin and Range Province
    Shooter:
    8x10 Format
    Thanks PE,


    Those are a 10 on my neatstuffometer.
     
  3. jstraw

    jstraw Member

    Messages:
    2,703
    Joined:
    Aug 27, 2006
    Location:
    Topeka, Kans
    Shooter:
    Multi Format
    So the yellow layer...before processing it looks quite diffreren than the magenta or cyan...yes?
     
  4. richard ide

    richard ide Member

    Messages:
    1,227
    Joined:
    Nov 8, 2005
    Location:
    Wellington C
    Shooter:
    Multi Format
    PE
    I was told many years ago (I think by my Kodak rep.)That your colour films are coated wet on wet with as many as 20 layers. Does that seem right? technically, what an amazing challenge to produce. I worked for a diazo coater many years ago so have a slight clue.
     
  5. Michel Hardy-Vallée

    Michel Hardy-Vallée Membership Council Council

    Messages:
    4,351
    Joined:
    Apr 2, 2005
    Location:
    Montréal (QC
    Shooter:
    Multi Format
    Does the "before processing" means "after silver development, but before color developer," given the visible grains?
     
  6. Steve Smith

    Steve Smith Subscriber

    Messages:
    9,083
    Joined:
    May 3, 2006
    Location:
    Ryde, Isle o
    Shooter:
    Medium Format
    That would be a coolness factor of 1000 milliFonzies!

    Steve.
     
  7. ben-s

    ben-s Member

    Messages:
    443
    Joined:
    Jul 12, 2006
    Location:
    Nottingham,
    Shooter:
    Multi Format
    This is fascinating stuff!
    I've looked at film under my microscope, and the grain structure is fascinating.
    I'll have to try a bit on edge, and see if I can see the layers.
    Any idea what mag these are at?

    Anyone got a spare microtome? :wink:
     
  8. Photo Engineer

    Photo Engineer Subscriber

    Messages:
    25,773
    Joined:
    Apr 19, 2005
    Location:
    Rochester, NY
    Shooter:
    Multi Format
    In answer to the questions above, the yellow layer is usually the coarsest grained, fastest of all emulsions, and yes, Kodak coats up to 20 or so layers at one time in a single pass. I believe that my max was 14 or so.

    You have to remember that this is also at very high speed, probably 3x faster than most of the industry standards, and orders of magnitude faster than many 3rd tier companies.

    PE
     
  9. jstraw

    jstraw Member

    Messages:
    2,703
    Joined:
    Aug 27, 2006
    Location:
    Topeka, Kans
    Shooter:
    Multi Format
    I'm not sure what the correct metric is....feet per second? How fast can those lines run?
     
  10. Photo Engineer

    Photo Engineer Subscriber

    Messages:
    25,773
    Joined:
    Apr 19, 2005
    Location:
    Rochester, NY
    Shooter:
    Multi Format
    Sorry, I would rather not discuss actual figures on the speed.

    PE
     
  11. jstraw

    jstraw Member

    Messages:
    2,703
    Joined:
    Aug 27, 2006
    Location:
    Topeka, Kans
    Shooter:
    Multi Format
    I understand.
     
  12. dmr

    dmr Member

    Messages:
    494
    Joined:
    Sep 9, 2005
    Shooter:
    35mm
    Thanks, PE. Please keep posting this kind of stuff. :smile: