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Light Plane Photography - Is my explanation correct?

  1. Jun 10, 2014 #1
    Dear Forum

    I'm an experimental photographer. During the last two years I've been developing a technique which I call light plane photography (LPP). LPP is a photographic technique that uses a plane of light and a camera to record photographs with unique optical effects.

    Here's three examples:

    psychodelic3.jpg serious-headache.jpg sneaky-hands.jpg

    Many more can be found on my Flickr page:

    These pictures are all out of camera, there's no software involved in creating the effects. They could be recorded using classic film photography.

    Now to my question: I've created a website where I try to explain and analyze the technique. My problem is that I'm more of an engineer and artist than a physicist and I am a bit unsure about some of the explanations I'm giving.

    You can find the abstract below in this post or here on my website:
    Part 1: About Light Plane Photography

    To sum it up, I'm mostly concerned about those two sentences:

    Is this from a strict physical point of view correct? Or at least if we ignore the obvious technical imperfection of the technique?

    Any corrections and comments are very appreciated!

    There's further information about LPP and a simple how-to here:

    Part 2: Effects
    Part 3: The Story Behind
    Part 5: How-To


    Light plane photography (LPP) is a photographic technique that uses a plane of light and a camera to record photographs with unique optical effects.

    A light plane is a thin plane of focused light from a specialized light source. Unlike light from a conventional, unfocused source, light from a suitable source for light planes does not spread to a three-dimensional sphere or a cone but is focused to a two-dimensional plane. In most cases, the light plane is the only light source in LPP and any ambient or stray light is avoided.

    In a typical setup, a camera is placed perpendicularly to a light plane, facing the light plane. The installation is inside a dark environment. Camera and light plane have fixed positions, long exposure times are used. As long as nothing is crossing the light path the recorded image remains black. As an object moves into the light, its contours are gradually illuminated. Over time, an image is recorded by adding the contours to a comprehensible projection of the object. Different regions of the image are recorded at different times.
    An object moves into the light plane, its outline is illuminated and becomes visible to the camera

    sceen-a11.jpg sceen-a21.jpg

    In contrast to traditional photography where subject movement is avoided in most cases, the movement and its choreography are central to LPP. When LPP images of people are recorded, it’s typically the model who is creating the image by moving through the light plane using a choreography.

    From the point of view of the camera, the light plane reduces our three-dimensional space to two dimensions. There is no depth, anything in front and behind the light plane is invisible to the camera. Any object crossing the plane has, at any given moment, only a two-dimensional contour.

    In the resulting image, one spatial dimension (depth) is exchanged with time (movement). Different regions correspond to different points in time. But unlike slit scanning, another photographic technique that adds time to the recording process, there is no fixed direction of the time dimension in a LPP image.

    It’s the movement (time) which is creating comprehensible images. Without movement all we would see is the 2 dimensional contours of the subject.

    A light plane photograph can be thought of as a parallel projection of a 3 dimensional space-time (two spatial and one time dimension).

    Laser diodes with line generating optics (line lasers) are the most common light sources in LPP. Line lasers create a very thin and almost perfectly parallel light plane. They are small and multiple line lasers can be calibrated into one combined light plane.

    When using conventional line lasers modules to create the light plane, the resulting photographs are monochromatic. To introduce more colors it is possible to use multiple planes with different wavelength lasers. In order to create near-real-color images, more advanced laser modules with 3 laser diodes (red, green and blue) can be used. The three colors are optically combined into one single RGB light plane.

  2. jcsd
  3. Jun 10, 2014 #2


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    I don't quite agree with this. I see this technique as more of an optical illusion than a look into the relation between space and time. LPP simply takes an image of a 2d plane over time, nothing more.

    (A really cool looking image I might add)
  4. Jun 11, 2014 #3
    Hi Drakkith

    Thanks for your reply!

    My argument here is that you end up with different parts of the image being exposed at different times, unlike a classic photograph (under most circumstances). So the time dimension kinda gets projected on the image. And with that, having two dimensions and time, I'd argue that we do play with space-time, if only in a pretty basic way.

    Also, I am not sure if the result is an illusion. After all, we're not "cheating" our brain here to create the effect. LPP rather records reality through a kind of filter which is different from how we are used to perceiving it, the beauty of it is that at the end we end up having comprehensible images.

    Again, thanks for your time
  5. Jun 11, 2014 #4

    Andy Resnick

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    Very cool! Your technique is similar to 'light sheet microscopy':


    And somewhat related to slit-scan imaging:

  6. Jun 11, 2014 #5


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    I see what you're saying, but I just don't agree. Consider that I can use a long exposure time to get star trails or trails from car headlights with a regular camera and setup. This is effectively the same thing except that I'm not suppressing a dimension.

    Okay. I can agree with this.
  7. Jun 11, 2014 #6

    Thanks for pointing that out, did not know about this particular technique.

    Another similar technique is scanning light photography

    Slit scanning is one of my favorite photography techniques. The problem with slit scanning though is it's relative complex recording process. You need to sync 2 or 3 different movements in order to get comprehensible images. This is very demanding for the models and it's very difficult to create results the way you planed them, most pictures show unexpected effects. On the other hand, the apparent randomness in the outcome is an appealing aspect of slit scanning, it pushes creativity.
  8. Jun 11, 2014 #7

    Would you mind to elaborate your argument? I would be genuinely interested in a strict physical point of view on this. And of course I want to avoid to spread pseudo-scientific bla bla...

    If it's correct that LPP projects a 2d-space and time on the resulting picture, isn't the whole technique a play with space and time, at least from a not so rigorous, artistic point of view?

    I've actually deliberatively chosen the particular expression "peephole into the complex physical relation between space and time" because I do understand that my explanation is not perfect. I choose the term "peephole" trying to indicate that there is much more to it than LPP is exposing.

    And of course, using the same argument, your example of light paintings and star trails would fall into the same category. Just a slightly different technique to record them (less physical filters).
  9. Jun 12, 2014 #8


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    I just don't see that it is a "peephole into the complex relationship between space and time that lies beyond our perception" any more than other photographic techniques.
  10. Jun 12, 2014 #9


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    Also look at streak cameras: an ultrafast photographic technique which makes a spatial record - the streak - from a rapid temporal event. Your techique reminds me of tose, but it is prettier!
  11. Jun 12, 2014 #10

    Thanks for the link. If I understand it correctly, with streak cameras a beam is projected onto a line over time, right?
  12. Jun 12, 2014 #11

    Now I understand your argument. Basically you saying I'm over-interpreting it. But isn't that my job as an artist/photographer, after all we need to give our work some special meaning otherwise we produce only ... pictures. :biggrin:

    Back to more serious discussion ... You are certainly right that you have a space and time projection in every photograph and that LPP is not different in this regard. But where LPP is different is that the projection of movement/time creates comprehensible images. Because of the missing physical filters, a normal photograph of movement is incomprehensible (a few special cases aside). Other techniques like light painting and star trails do create comprehensible images, but the effect works only with active light sources. As a result only the path becomes comprehensible, not the object itself. In LPP a passively illuminated object/subject can be projected over time.

    But anyway, this is punctiliousness on my part :rolleyes: I presented the sentence here out of context. In the original text it is part of a description of the optical effects of LPP. It certainly does not intend to single out LPP as the only technique achieving this. It's meant to simply say that LPP is a play with physical dimensions. I deleted the part "that otherwise lies beyond our perception", I agree with you that this is exaggerating it.
  13. Jun 12, 2014 #12


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    How about, "LPP produces unique images by substituting one spatial dimension with time"?
    That seems to be an accurate description of how it works.
  14. Jun 13, 2014 #13
    Thanks for the suggestion, I like it. There's actually already a very similar sentence:
  15. Jun 13, 2014 #14


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    Over interpreting ... no
    giving it a false meaning ... yes

    yes, but not by saying that it is something that it isn't :wink:

  16. Jun 14, 2014 #15

    Thanks for joining the discussion :-)

    Just to make sure, are you referring to to the first part "peephole ... space and time" or the second part "... otherwise beyond our perception"

    Thanks, Jiri
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