Although lenticular technology has been widely used for more than half a century little has been done to explore its potential artistically. It is as magic as it is technical, and delightfully interactive. You have seen lenticular images: they come as winking prizes in Cracker Jack boxes, portray 3D Jesus in the garden of Gethsemane or show beautiful women with (and suddenly without) garments to cover their shame. The recent surge in American patriotism has given rise to various combinations of eagles, flags, fireworks and George W . . . in glorious lenticular style. What has been missing, except for a handful of cases, is a deep exploration of the media for purely artistic reasons.

Lenticular images have two tricks up their sleeves: change and depth. The change is often a simple flipping between two images but can also be a smooth transition between many images like you would find in a short animation sequence. The depth effect is more complex but essentially creates an illusion that things sit behind, on, or in front of the plane of the image. The amount of perceived depth is dependant on several factors and can vary from a few centimeters to many inches, even feet on larger displays. Any effect is created because the plastic surface that sits on top of the image is in fact a series of cylindrical lenses and the image behind it has been sliced or "interlaced" into strips that match the resolution of the lenticular sheet. The viewer's orientation to the lens then becomes the critical part, and with both eyes open and head moving slightly side to side the resulting effect can be seen clearly.

The depth effect is the easier of the two to create well, but perhaps a bit more sophisticated technically. It relies on the stereoscopic nature of our vision, which sees slightly different information in our right and left eyes. This phenomena has been reproduced dozens of times in movies through the use of anaglyph techniques (red and cyan glasses), or in the simple stereo pairs that were common over a hundred years ago. The wonderful thing about lenticular imagery is that it does not require the viewer to wear special glasses to perceive the effect. Furthermore a dozen or more pictures are typically interlaced together which creates an even greater sense of depth than a simple pair of images can provide.

As stated earlier the two image "flip" is the most common motion trick and often the most effective. Although 24 (or more) distinct images can be used with commonly available lens material the general rule with motion is to limit it to a few frames. In the commercial lenticular world the possible effects will be listed as flip, zoom and morph. . . . but that is an arbitrary subset of the range of potential motion possibilities. The potential for change imagery is limited only by imagination.

Once the individual frames are made they must be interlaced together into a single image. This is most effectively achieved with the help of special software, but was traditionally executed in the darkroom. The interlaced print is then mounted with clear adhesive to the smooth side of the lenticular sheet and rolled flat. The result is magic.

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