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  1. #21
    Donald Qualls's Avatar
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    Many years before holograms were printed on reflective Mylar or similar material, they were made on glass plates or photographic film. In fact, holography predates the invention of the laser; the first holograms were made with mercury vapor light, filtered to make it monochromatic, IIRC in the 1930s (the first ruby laser was demonstrated in about 1957, as I recall). Lasers made it easier because they produce bright, monochromatic, and spatially coherent light.

    I've seen white light viewable rainbow holograms on what was originally B&W film -- the colors are produced by phase interference; differences in thickness of the emulsion between exposed, developed, and bleached regions vs. unexposed regions on a phase hologram produce both the colors and the inteference patterns that produce the three dimensional real image. In fact, the first phase hologram I saw predated the introduction of reflective mylar...
    Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.

  2. #22
    r-s
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    On the topic of interference effect films, rather than one more holographic film, usable only by a select few with the requisite (and expensive/massive) hardware, I'd like to see someone bring to market a Lippmann process color film -- the only TRUE color emulsion ever created. (The Foveon sensor is tangentially/conceptually related to Lippmann's work, but it really doesn't even approach what he accomplished. For all its "innovative" aspects, Foveon's product remains a mere three-color platform, as well as a "D"-thing.)

    The fact that Lippmann's discovery happened back in the late 1800s only adds to the mystique.

    I don't think the current brouhaha over mercury need be an obstacle either. There are other room-temperature "liquid metals" available today, without the alleged safety issues affecting mercury usage.

  3. #23

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    Quote Originally Posted by Photo Engineer
    Virtually any B&W film can be used for making holographs. The success is a matter of the efficiency of the film to interact with the laser light and then form the interference patterns. This BTW includes just about all B&W films anyhow as long as you test them first and use them under optimum conditions of exposure.

    ...

    PE
    I recall that one of the most successful earlier holographic films was Technical Pan (and before it the SO High Resolution Plate). If there is some speed to the new Fuji film, it might be worthy of a few experiments in cameras.

  4. #24

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    At the prices mentioned I will experiment elsewhere.
    Claire (Ms Anne Thrope is in the darkroom)

  5. #25

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    Holographic film is black and white, with possible sensitization in a color range tied to the user's laser color (as mentioned above), or it could be panchromatic. However, it has two characteristics that distinguish it from ordinary B/W film: to record a hologram you need a resolution of 3,000 lines per mm, better 5,000 or 10,000 (the latter if you want to record blue or all visible colors). The information recorded, normally without a lens or mirror for focusing, is an interference pattern and the pattern's scale of detail is set by the wavelength of light (visible light has wavelengths between about 4/10,000s and 6.8/10,000s of a mm). Ordinary high resolution film resolves about 125 lines per mm. Since the resolution of holographic film is 50 to 100xs normal, the speed is correspondingly less, around ASA 0.5. It also lacks antihalation backing, since many holograms require the laser light to travel both ways through the emulsion. Emulsions are made on both film and glass plates. Makers include Slavich, Color Holographics, Yves Gentet, and now Fuji. (Agfa and Ilford both withdrew from the market.) It can be used for non-holographic art purposes, but keep the slow speed and lack of antihalation in mind. People here interested in holography might look at the forum Holographyforum.org.

  6. #26

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    Also as mentioned above, films similar to holographic films can be used in the Lippmann process, announced in 1891. It records full color in interference patterns on black and white film. Since ordinary light is impure, it can not record 3-D, as laser light, which is very pure, can. Lippmann created the interference by making a plateholder with a rear pocket to hold a thin layer of mercury. He loaded one of his home-coated super-high resolution plates into the holder with the emulsion facing away from the lens, filed the pocket with mercury, and shot (with an ordinary plateholder camera on a tripod). The light passed through the glass and emulsion, bounced off the mercury mirror and interfered with the incoming light in the emulsion. Exposure times, due to the high resolution/slow speed were around 30secs to a minute in bright sunlight, at f/4-f/5.6. He won the Nobel prize in Physics for this in 1908.

    There is also a section of the Holographyforum.org devoted to Lippmann photography. Anyone interested in either subject would be welcome to email me or visit me to see holograms or Lippmann images. I am at walschulr@hotmail.com and live in San Francisco. Lippmann photography is my special passion.
    Last edited by William R. Alschuler; 10-27-2006 at 05:04 PM. Click to view previous post history. Reason: additional text

  7. #27
    r-s
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    Here's a question regarding the Lippmann process: Does it require panchromatic emulsion? (I realize that pan films were in fact available back in that era -- the Library of Congress's amazing "The Empire That Was Russia" presentation is evidence of that fact.)

    But I'm wondering if perhaps Lippmann photography doesn't require spectrally sensitized emulsion. When the infinite "layers" are formed at each depth in the emulsion at which the interference "events" occur, is the "exposure" based on an actual (at time of exposure) "color" light present within the emulsion (as a result of the interference at that point), or, is (perhaps) the exposure a result of white (or "near-neutral") light that results from the colliding waves?

    This is all way above my pay grade. I'm no physicist, not by a long shot. But, I'd like to know the answer, just in case some day, somehow, I'm in a position to try to make some Lippmann images of my own.

    Edited to say that "results from the colliding waves" was not the best choice of words, I meant to say something along the lines of "occurs at the point of collision", i.e., when two wave fronts of white light collide, is the result a "white light exposure" within the emulsion at that particular depth?

    Edited again to add that it's probably not that simple, since the light in question won't be "white light", i.e., if the light is reflected off of a red dress, it's not going to be "white" light, so I guess he probably did have to sensitize his emulsion. Oh well.
    Last edited by r-s; 10-27-2006 at 07:46 PM. Click to view previous post history. Reason: Clarification.

  8. #28
    r-s
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    BTW, for anyone who hasn't seen the LOC presentation mentioned above, here is a treat you won't soon forget:

    "The Empire That Was Russia"

  9. #29

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    Quote Originally Posted by r-s View Post
    BTW, for anyone who hasn't seen the LOC presentation mentioned above, here is a treat you won't soon forget:

    "The Empire That Was Russia"
    Physicist James Clerk Maxwell also achieved additive color photography in 1861.

  10. #30
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    I'm pretty sure that you'd need a panchromatic emulsion for this.

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