I have some questions about what I for lack of knowledge about the proper name call 3-D or Holo cards. The type of cards (I’ve seen it on postcards, greeting cards etc) I mean are those where either the motif on the card changes depending on the angle you view it from or where there is an illusion of depth. The cards seem to work by having a textured surface of transparent plastic that I guess is what makes them work by changing what you see of the two or more images that are printed on the card.
I recently saw it on a magazine cover as well, it was some type of movie magazine with Spider man on the front. Does anyone know what I am talking about?
What I want to know is:
What are they called?
How do they work?
Is it possible to make one yourself? I have a CD where the case has the textured surface on the front and I can see that the booklet image(s) are mixed together. Maybe there is some software that has this as a function?
They are ‘thick’ or ‘white light’ holograms which don’t require a laser to reconstruct them.
Holography invloves encoding the phase and the amplitude of the light forming an image in recorded interference fringes. In these holograms, you encide a different image at different angles (so that the interference fringes form different planes).
Tricky, but not impossible. You’ll need a decent laser, darkroom, holographic table and a good supply of expensive emulsion-covered glass plates for stability. A tiny vibration of a quater of a wavelength will ruin it.
I believe the OP is talking about lenticular printing. Each groove on the transparent plastic sheet acts as a lens, and magnifies a portion of the underlying image while masking the rest. It can be used as a “motion” picture, i.e. if you walk past the poster (or tilt the card) the image appears to move. Or it can be designed to send a different image into each eye, creating a 3-D effect.
In addition to the (quite recent) patents shown at scr4’s link, there are patents going back to the '60s for this use of lenticular material, and a lot of research going back to the '30s. Victor Anderson, the genius who invented mass-produced lenticular printing, co-founded Vari-Vue with his wife, and ended up dominating 3-D printing for years. Victor kept working through his 80s, long after Vari-Vue was bought out (I nearly married Victor’s daughter, who I call “the wiggle-picture heiress”) A history of 3-D and lenticular printing can be found here. (Warning: PDF file)
Thanks, lenticular printing is exactly what I was looking for. I tried some googling before posting but only found the laser holograms that Sentient Meat talks about.
Mea culpa - they’re not really holograms at all. The technique I described is used only in high quality holographic capture of famous artworks, historical artefacts etc. and is incredibly expensive and labour intensive - not at all suitable for commercial assembly line items like credit cards and cereal packets.
Yes and no. While true holograms are more expensive than lenticular images, they are used in some mass-produced items. National Geographic has had a holographic cover at least twice, and Sports Illustrated once (an image of Michael Jordan). Many credit cards now also include true holograms, albeit very poor quality ones, and I’ve seen a textbook (on holography, of course) which had one on the cover.