Shadowgrams and Schlieren photography

Craft & Design Photography & Video Science
Shadowgrams and Schlieren photography
false_color_revolver_shadowgram.JPG

False-color shadowgram of gunshot from a .357 magnum by Gary Settles at Penn State university.

The New York Times has an awesome slideshow of shadowgrams and Schlieren photographs, created by engineering professor Gary Settles, which accompany a 2008 article about his work at Penn State’s Gas Dynamics Lab. The method, which can produce fantastic visualizations of fluid flow in turbulent systems, is amazingly simple. I am surprised there aren’t more hobbyists doing it.

14 thoughts on “Shadowgrams and Schlieren photography

  1. Daniel Ashbrook says:

    If it’s so simple, how about a link telling us how?

    dan

    1. JTau says:

      Just call me dumb but that wikipedia quote made no sense to me, even with the help of a dictionary. The rest of the world may not be as apt in physics – hence the lack of Schlieren photography among hobbyists (which may also include lots of soccer moms), or any tutorials for that matter.

  2. Sean Michael Ragan says:

    There are no online tutorials that I know of, but like I say, it’s incredibly simple, as a minute’s research reveals. From the Wikipedia article on Schlieren Photography:

    “The basic optical schlieren system uses light from a single collimated source shining on, or from behind, a target object. Variations in refractive index caused by density gradients in the fluid distort the collimated light beam. This distortion creates a spatial variation in the intensity of the light, which can be visualised directly with a shadowgraph system.”

    Which amounts to:

    “Make bright, focused shadows of the system you want to study and photograph them while the system is in operation.”

  3. Jesse says:

    I googled for a bit and didn’t find a whole lot of info for the DIYer, however this image gave me an idea:

    http://www.americanscientist.org/Libraries/images/2005122153046_846.jpg

    Use a tightly focused flash, small combiner and old projector screen and you should be able to make high speed Schlieren images with the high speed photo kit from the maker store.

  4. Ian Smith says:

    I have been playing around with this for about a year and have a web page up about it.

    It IS simple.. once you figure out all the “obvious” things that tend to get left out when describing it. It took me a while to get all the details right, and shortly I hope to add to my page a better description of what is going on.

    http://www.ian.org/Schlieren/

    The only hard part to find is the mirror. A six inch spherical mirror from Edmund Optics will run about $50 which is not too bad. Mirrors get expensive FAST as they get bigger.

    1. Sean Michael Ragan says:

      Thank you, thank you, thank you! Your page will be up on the feed Monday morning.

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I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I am a long-time contributor to MAKE magazine and makezine.com. My work has also appeared in ReadyMade, c't – Magazin für Computertechnik, and The Wall Street Journal.

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