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Typically the creation of a hologram involves lasers and various other expensive equipment and materials. William J. Beaty figured out a low-tech way to create your own holograms using a simple abrasion technique that requires only a compass and a chunk of plastic. He came across the idea while walking through a parking lot, noticing strange hand prints that seemed to float above or deep inside the surface of polished car hoods.
The images were naturally-occurring holograms. The owner of the car had obviously polished the hood with a dirty mit, and the millions of particles of grit in the mit traced out millions of nearly-parallel scratches in the black paint. The particular hand motion had created a geometry of abrasion patterns which turn out to be nearly identical to the interference patterns which make up those embossed-foil Benton whitelight [holograms].
So how do you make one? All you need is a spanner (compass with 2 needles) and a chunk of hard plastic such as Lexan. For simple flat shapes, you just draw the reference shape below where you want the hologram to appear. Set the diameter of the spanner to an inch or two, put one of the points on the shape and score a small arc across the plastic. You then repeat this process for a bunch of other points on the shape, leaving a number of small arc shaped scratches. When you observe the scratches in the light, you'll see a hologram of the shape that appears to float beneath the surface of the plastic.
The image above, from William's site, is actually a stereo photo of one of his holograms. You can cross your eyes to see the effect. The cube that reflects from the scratches appears different based on the angle you view it.
The depth of the hologram is related to the width of the spanner, so you can actually create three dimensional holograms using the same technique. William's FAQs have more details on doing this, as well as hints for creating opaque shapes that have other objects hidden behind them which are only viewable from certain angles.
Abrasion Holography - Link
Not a hologram, just a stereo image. Come on now.
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John,
Read closer. It's a stereo image _of_ a true hologram. The side-by-side image above are two perspectives of the same sheet of plastic. You can see that the visible image of the cube is different from two viewpoints.
That's what's so cool about this. It's almost magic that you can create a holographic effect just by making a bunch of scratches in plastic.
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This is just crying out for someone to generate complex pictures using CNC.
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This looks really cool. I'd like to see a video of the process & the resulting image though!
Carl, great idea using CNC to create complex images.
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There's an instructable over at http://www.instructables.com/id/Make-a-Tool-to-Draw-Scratch-Holograms!/
that describes building a tool out of a Dremel to make the process of drawing a scratch hologram easier.
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> This is just crying out for someone to generate complex pictures using CNC.
The scratches need to be be almost perfectly smooth with no jaggies at all. Normal CNC doesn't work, but a couple months ago Evan at homeshopmachinist.net found that "drag engraving" does reduce the jaggies enough, see:
http://bbs.homeshopmachinist.net/showthread.php?t=27081
> This looks really cool. I'd like to see a video of the process & the resulting image though!
Lol, I was finally going to do a video just last weekend, but it rained the whole time. These look great in direct sunlight, poor under most light sources except high-power pin spots.
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