I did this in high school (late nineties). Won a bet with my physics teacher.
posted by ryanrs at 10:50 AM on May 2, 2009

They've been here before, but the demonstration video is new and neat--it's a much better way of seeing these in action. Nice post. (Also, there's a more mathematical analysis for those with institutional access.)
posted by Upton O'Good at 10:53 AM on May 2, 2009

Is this the sort of thing you'd have to have two eyes to appreciate?
posted by leapfrog at 10:55 AM on May 2, 2009

why do people who do these things always sound like Muppets?
posted by Lipstick Thespian at 11:01 AM on May 2, 2009 [6 favorites]

If it doesn't ask me to please state the nature of the medical emergency then it's not a hologram one should care about!
posted by mightygodking at 11:07 AM on May 2, 2009 [1 favorite]

Yeah, remember that here before, but thankful for any new material on the subject. Thanks, hippybear.
posted by Durn Bronzefist at 11:08 AM on May 2, 2009

This is a nifty optical effect, but it seems to be operating on a completely different principle to holography. The giveaway is that the image changes when you tilt it left and right, but not up and down. From the paper Upton O'Good cited, it looks like these "scratchograms" are explained purely by scattering, and have nothing to do with interference effects.
posted by teraflop at 11:13 AM on May 2, 2009 [1 favorite]

Excellent use of the "groovy" tag, by the way.
posted by TedW at 11:19 AM on May 2, 2009 [3 favorites]

I don't care about holograms until they're at least as advanced as the little version of Princess Leia from A New Hope.
posted by Pope Guilty at 11:43 AM on May 2, 2009

Teraflop: I'm hesitant to call them holograms also, since they're a pretty far cry from the original zone-plate-style holograms¡ª but the ¡°yes, they are¡± link gives a pretty good argument for considering them holograms at least as much as the common white-light ¡°rainbow¡± holograms are. (Also, the scratch-holograms work by reflection or refraction, not scattering.)

(Also also, Metafilter's Own.)
posted by hattifattener at 11:55 AM on May 2, 2009 [2 favorites]

awesome...this must be a similar process to how they make the canadian maple leaf holographic gold coin (i learned about it from a documentary on gold...though they didnt go into much detail about it, it was made clear that the hologram wasn't applied to the surface, but actually stamped into it.)

and while i'm here, the coolest hologram i ever saw was in the art gallery section of the new york museum of holography (which i believe is now defunct) way back in the 80s...it was a 'combination' piece that involved an actually physically present sculpture of a man on a ladder with a rag combined with a projection hologram of the 'window' he was cleaning hovering in space in front of him. here's the weird part: from one side the window is a simple square, but if you walk around to the other side, its a circle. (both sides are rainbow-colored depending on your angle, like a cd). question: how'd they do that?
posted by sexyrobot at 3:47 PM on May 2, 2009

billb's MeFi comments are pretty interesting in and of themselves!
posted by mwhybark at 4:25 PM on May 2, 2009

I've just tried it, and it's pretty cool. I made the mistake of trying to do too small and detailed a drawing (the results are pretty low-resolution), but you can still roughly see the results. The non-label side of a writable CD has nice soft plastic that takes the scratches really well.
posted by rifflesby at 5:57 PM on May 2, 2009

That is crazy! What kind of material is that?
posted by eiro0701 at 10:48 PM on May 2, 2009 [1 favorite]

looks like black plexiglas
posted by sexyrobot at 11:26 PM on May 2, 2009

Is it just me or does this guy sound like Carl Sagan?
posted by hillabeans at 8:36 AM on May 3, 2009

billb's MeFi comments are pretty interesting in and of themselves!

Indeed, in fit of hyper-nerd self-referentiality, I took a photo of him uploading one of those comments. When I google the terms "bill beaty metafilter" this photo comes up.

Previously.

Previous YouTube linkage.

I propose that around the time of the winter solstice, a mash-up be created that combines amasci.com with William S. Burrough's The Junky's Christmas, which shall become an annual Metafilter homage to both unique individuals.
posted by Tube at 9:42 AM on May 3, 2009

I could listen to this guy talk about anything ever. His voice is adorable.
posted by The Devil Tesla at 3:21 PM on May 3, 2009

Awesome, and all by an accident of observation!
posted by Ogre Lawless at 12:06 PM on May 4, 2009