What are those holograms called if not "hologram"?

October 11, 2004 1:20 PM

Ever since I was a kid it's always baffled me what the technical term for those 'magic' rulers is - the ones that display an image, and as you tilt it in the light, it displays another, or multiple images, to give the impression the image is moving. They were usually cartoon based, depicting Transformers or some similar childhood cult characters. People always told me to accept they were called holograms and be done with it, but I am convinced they are not holograms, as holograms are a 3D image, or should I say give the illusion of a 3D image, which these rulers did not, only a moving image. Can anyone shed any light on the matter?
posted by si to Science & Nature (10 answers total)

I could've sworn that was called a refraction grid, but google is only bringing that up in terms of advanced holography, so maybe not.
posted by PinkStainlessTail at 1:25 PM on October 11, 2004

They're called "lenticular" images. The grooves on the ruler are little teensy lenses that force light to be reflected at a certain angle. The two (or more) images you see when you move the ruler are actually printed in consecutively interpolated segments (e.g., unicorn standing, unicorn raising mighty hooves, unicorn galloping away).
posted by LimePi at 1:44 PM on October 11, 2004 [1 favorite]

Er, some of these lenticular images can also appear to be three-dimensional, if the images shown are just tweaked a bit to compensate for our binocular vision.
posted by LimePi at 1:47 PM on October 11, 2004

The album "Ænima", by Tool, uses this kind of thing in a way that makes it easy to figure out. The case is grooved, and the CD booklet (removable, of course) has the interlaced images printed on it.

... some of these lenticular images can also appear to be three-dimensional...

I saw one like that for the first time a couple of weeks ago, on a bus stop shelter in Chicago. Freaked me the hell out until I figured out how it was done.
posted by Johnny Assay at 2:49 PM on October 11, 2004

What LimePi said. I work for one of the few companies in the US that can do large-format lenticular stuff; we've made some pretty sweet marketing pieces. I have several of them up in my office.
posted by SpecialK at 3:20 PM on October 11, 2004

Special K -

How much do lenticular things cost? Is it within the realm of a poor band that wants to do some neat packaging?
posted by mildred-pitt at 3:30 PM on October 11, 2004

I've seen lenticular images, and even knew that was what they were called, but I've never seen one on a ruler.
posted by jjg at 3:44 PM on October 11, 2004

mildred-pitt:

A while ago I saw a stand at a show where a CD duping company was offseting cases with the grooved front, so I guess the lenticular CD case must be mass produced somewhere. Maybe. Tried googling, but no joy...
posted by Flat Feet Pete at 4:01 PM on October 11, 2004

Lenticular images add about $1-2 each to the cost of a 1000-CD run.
posted by tomierna at 6:01 PM on October 11, 2004

The album "Ænima", by Tool, uses this kind of thing in a way that makes it easy to figure out. The case is grooved, and the CD booklet (removable, of course) has the interlaced images printed on it.

I have an Iron Butterfly album that does that as well. Pretty cool.
posted by salmacis at 2:56 AM on October 12, 2004