This is a tough one.
Anyone know how this effect is achieved?
From the images it appears there is a transparent sleeve (acetate) printed with fine vertical lines. Same for the inside paper card.
But how is it that the text disappears inside the card? Hard to figure out without the real thing, but if anyone has seen such a thing up close, please explain! :)
Similar to the focal decoder : http://3dimages.co.uk/focal_decoder.html
Maybe the white lines on the outer sleeve is actually opaque and not transparent? And the black is semi-transparent? That's amazing. I haven't paid much attention to it, thinking it was just the usual moire. Should've known, it's Stefan.
If you look closely at the top photo, it appears that the type is on the substrate (card) and that at least the inner sleeve is transparent. If the white lines on the outer sleeve were opaque, what's going on in the right-hand side of the top picture and everywhere in the bottom picture would not be possible. More likely, the "similar to Focal Decoder" argument is correct: the sleeves are actually lenticular lenses which only allow the image on the subtrate to show when they are in perfect register. Or not...
Video on Amazon seems to shed some light on how this works.
http://www.amazon.com/gp/mpd/permalink/m2VAQD35OJLSMW
and these books seems to be relevant
http://www.amazon.com/Optical-Designs-Overlays-Pictorial-Archive/dp/0486...
http://www.amazon.com/Visual-Illusions-Motion-Moire-Screens/dp/048629571...
Still, would love to get some templates to design such a card.
The latest issue of Wallpaper magazine comes with an acetate like this to similar effect. Perhaps you can get hold of a copy, might help you figure it out. I'm not sure that it is exactly the same but it might help.
Looking again they are perhaps dissimilar.
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