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  1. #31
    michaelbsc's Avatar
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    Quote Originally Posted by holmburgers View Post
    Ok... I must've been confuzzed on the beam splitter thing.. I seem to recall a discussion about beam splitters inside CRT TV's, but, regardless..

    ...

    Imagine a one-shot 35mm or 120 camera! You could have 3 rolls of film in 1 camera. That would be awesome...
    That was a Phillips prism we were talking about. Much more elegant, much more expensive, and probably not happening in my life time without a winning lottery ticket. The Phillips prism would have far less light attenuation, but all the modern ones you can find are sized for microscopic CCDs. I found a few places that would make one for prices that would make a military project sweat.

    Edmunds has beamsplitters that are 50/50 and ones that are 65/35. So my thinking, without having done all the research, is that you can maybe take care of the filter factors in the camera by how much light goes to each plate.

    As far as using roll film is concerned, I suspect that you would have to cut the frames apart for registration anyway. So I was thinking that plain old film holders would be easier with sheet film. I have some 2.25x3.25 film holders that I got for my Baby Graphics 2x3.
    Last edited by michaelbsc; 08-05-2011 at 12:54 PM. Click to view previous post history.
    Michael Batchelor
    Industrial Informatics, Inc.
    www.industrialinformatics.com

    The camera catches light. The photographer catches life.

  2. #32
    CMB
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    Quote Originally Posted by holmburgers View Post
    I think that these Curtis and Devin one-shots used half-silvered mirrors,
    My 5x7" Devin-McGraw has gelatin pellicles and my Curtis Color Scout has silvered mirrors.

  3. #33
    John Jarosz's Avatar
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    The book by Paul Outerbridge "Photographing in Color" has an appendix with pictures and information about one-shot cameras. It's kind of hard to find and pristine copies are really expensive, but if you find an old beat up copy the information in it is pretty cool. Most people are only interested in the tipped-in photographs.

  4. #34
    smieglitz's Avatar
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    If anyone is interested in some NOS 5x7 tricolor holders I have 9 for sale in the classifieds. I've reduced the price considerably from the original ad.

    NOS 5x7 Baco/Graflex Tricolor Holders

  5. #35
    smieglitz's Avatar
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    I forgot to mention that the tricolor holders I have for sale are plate holders, not film holders.

  6. #36
    holmburgers's Avatar
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    I saw those and wondered about them. They would certainly make a collector very happy.

    I'm still reeling from the fact that Charles has 2 one-shot cameras...
    If you are the big tree, we are the small axe

  7. #37
    holmburgers's Avatar
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    If you are the big tree, we are the small axe

  8. #38
    holmburgers's Avatar
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    Friday Daydreaming

    I've learnt a bit about a unique kind of color camera by studying F.E. Ives' Hess-Ives Hicro Camera (found here, though many different models seem to have existed). It used a special tri-pack with one element that folded down at a 90° angle (the blue sensitive element) relative to the remaining two elements (green & red sensitive plates). Then, a yellow dichroic reflector lowers down from within the camera and bisects this right angle at 45°. It throws blue light onto the blue plate and allows green & red light to pass to the bipack behind it.

    U.S.P. 1,287,327 generally describes the Hicro camera.
    Then, patent 1,238,775 describes the dichroic reflector and how to make it (warning... it's super easy!)
    980,961 describes the film pack I believe, though I haven't actually read this one yet.

    Ives refers to this dichroic reflector as a "color selective transparent reflector", and it represents an advantage over a half-silvered mirror or beamsplitting prism in that only one color is reflected and all else are passed. A half-silvered mirror would split all light 50/50 and this would require further attenuation by a color selective filter to isolate the primary light. The dichroic reflector takes care of both at the same time, resulting in less loss.

    A dichroic reflector is an interesting thing; "...the sum of the reflected rays is in color substantially the complement of the sum of the transmitted rays."

    I have some pictures of the Hicro camera interior that I will post if I get permission from the author of said pix.

    OK, and now for something completely different...

    Michaelbsc has mentioned several times about using a tri-color beamsplitter to achieve a very efficient separation of light into red, green & blue elements. It turns out these Phillips prisms use dichroic reflectors (maybe you knew this... I didn't!). These might be inside every old camcorder sitting in your closet and I'm wondering if you couldn't just open one up and cannibalize it. Or you can get them for mildly reasonable prices on eBay (at most $200, but O.B.O.). Or one could go for broke (or just broke) and call up these folks.
    If you are the big tree, we are the small axe

  9. #39
    holmburgers's Avatar
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    Hess-Ives Hicro interior photos, courtesy of Bob Lansdale. I think Bob intended to clean up the photographs by erasing the props & improving the presentation, but I'm too impatient... so don't blame his taste, blame mine!

    Attached Thumbnails Attached Thumbnails Hicro 1.JPG   Hicro 2.JPG   Hicro 3.JPG  

  10. #40
    holmburgers's Avatar
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    Here's the Jos-Pe tri-color camera.

    http://www.prophoto-online.de/images...tografie-0.jpg

    All I really know about the Jos-Pe process is that it was a dye-imbibition color printing process that, I think, used relief matrices.
    Attached Thumbnails Attached Thumbnails Jos-Pe Camera.JPG  

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