You have seen amusing and catchy images on ads which wink, smile or throw a kiss at you, run, shine, or change messages with your viewing angles and do many such amazing things. Have you ever thought of how these images are produced? It is the magic of a technology called lenticular printing. Lenticular printing is a technique which uses lenticular lenses (the same technique used for 3D displays) to produce images having an illusion of depth, or the ability to move or change as the viewing angle is changed.
lenticular printing technology was invented in the 1940s but has developed further just recently to add more motion and depth to the images. Originally it used to be displayed on novelty items and created something called “wiggle pictures” or “flicker pictures”. Today it is used as a marketing technique to show products moving. Latest advancements in large-format presses have made it possible to use oversized lenses in lithographic lenticular printing.
Technique
Lenticular printing involves many steps of producing a lenticular image from minimum two images and merging it with a lenticular lens. This technique can be used to produce various animation frames (for a motion effect), offsetting different layers at various increments (for 3D effect) or just to show a set of interchanging images which may seem to convert into each other. Once these various images are gathered, they are leveled into individual various frame files and then combined digitally into a single last file in a process known as interlacing.
The interlaced images can be directly printed to the back of the lens (smooth side) or to a substrate (preferably a synthetic paper) and then laminated to the lens.
Ghosting
Ghosting is an unattractive result of lenticular printing which takes place when more than one image is displayed at particular viewing angles. This happens when images on the same lenticular lens have excessive color contrast, mismatched pitch, poor registration or too many frames.
Types of Lenticular Prints
Lenticular prints are of three types depending upon how big a change in viewing angle is needed to change the image.
Transforming Prints – In transforming prints, two or more very different images are used and the lenses are made to require a comparatively large change in viewing angle to shift from one image to the other. This makes it easy for viewers to see the original images, because small movements don’t cause any change. Large movement of the print or the viewer makes the image flip from one to the other.
Animated Prints – In animated prints, the distance between various viewing angles is “medium”, thus when both eyes generally see the same picture, moving a bit shifts to the next picture in the lineup. Normally several sequential pictures are used with just a small difference between an image and its next image. This makes an illusion of movement, or can produce a “morph” or “zoom” effect, wherein a part of the image increases in size or changes its shape as the viewing angle changes.
Stereoscopic Effects – In stereoscopic effects, the change in the angle of viewing is small, thus each eye can see only a little different view. This produces a 3D effect without having to wear specialized glasses. E.g. 28 images are produced by the Dolby-Philips Lenticular 3D display.