The Nimslo camera from the 1980s used four lenses to capture images from slightly different viewing angles. Lenticular prints
could be ordered from special print shops.
Although they are not yet used for photographs, there are 3D printers that can be programmed to print solid 3D objects. Increasingly used to do one-off prototypes they are also used to print food. By replacing ink cartridges with food ingredients, a printer can be programmed to print 3D cookies and other food items, building them up one layer at a time. To learn more, visit fabathome.org
. Another service prints 3D models of jewelry using wax which is then cast in silver.
Click to visit LenStar.org, with sections on how lenticular works and its history.
Here a detail is blown up to better show the interlacing. The interlacing is exaggerated to better show the effect.
For years there have been novelty cards that display one image when held at one angle and another image when tilted slightly. You may have seen them on CD jewel cases, movie posters, postcards, souvenirs and novelty items. The principle behind these cards, called lenticular prints
, was first demonstrated by Gabriel Lippman in 1908. (Lippman also developed a color photo process for which he was awarded the Nobel Prize for Physics in 1908).
An old political button changes from Nixon to Agnew as it is tilted.
Lenticular prints can be made so they flip back and forth between two or more different images, display short animations and movie clips, or display autostereoscopic 3D images. When viewing one of the 3D prints it seems as if you can peer around foreground subjects as you turn the card. Using a stereo pair you’ve captured you can make lenticular prints yourself or have them made for you at a reasonable price by on-line services such as start3d.com and Fuji’s seehere.com.
The 3D effect is much like a lenticular autostereoscopic display discussed in the previous chapter. The two images in a stereo pair are interleaved and then viewed through an optical layer covered by long cylindrical lenses (lenticules) arranged in parallel rib-like rows so they look somewhat like transparent corduroy. Each or the lenses has a focal length equal to the thickness of the clear plastic sheet on which it is molded so it magnifies one of the many narrow strips of the image behind it and casts the thin image strips from the two images to different eyes. As a result one eye sees slices from one image in the stereo pair and the other eye sees slices from the other image.
As you view a lenticular image from different angles, the vertical lenses cast the interlaced strips from one image in a stereo pair to one eye and stripes from the other image to the other eye. Since each eye sees only strips from one of the images you see a 3D effect. Courtesy of www.lenticularblog.com
3D ANAGLYPH PRINTER
Kodak is introducing software that will automatically combine and print stereo pairs as anaglyphs. After uploading the images to your PC Kodak's AiO Printer Home Center software combines the two photos into one 3D anaglyph image ready for printing and viewing with red/cyan glasses.
Preparing Lenticular Images
Since a lenticular image can display one image after another as you change your angle of view, it can create an animation much like an old fashioned flipbook. For this reason, each image is called a flip
. For a 3D effect you can use the minimum two flips. However, smoother effects can be created by generating a multiview 3D with multiple flips as discussed in the sections on Wiggle 3D in Chapters 1 and 4.
Once you have the images you are going to use, you use interlacing software to cut them into very narrow vertical strips. The software then interlaces these strips like a perfectly shuffled deck of cards. If two flips are being created, the first band is a strip from image 1, the second from image 2, the third from image 1, and so on. The software then saves the interlaced image in a file ready for printing.
Printing the Images
To create the final print the interlaced image is printed on the back of a plastic lenticular sheet so the interlaced strips are in perfect register with the lenses. You can do this on many high-quality inkjet printers that have a straight-through paper path that can accommodate the thickness of the lenticular sheet.
- The pitch of lenticular sheets range from 10 lenticules per inch to over 200. Higher pitches reveal greater detail.
- Images that work best for prints are horizontal with the most important subjects 10–16 feet (3–5 meters) from the camera and with the background much farther away.
- Images that don't work as well are long distance shots or close-ups.
- Since images are interlaced so they fit into the same width as one full-resolution image, strips from each image are lost, reducing the image’s horizontal resolution. If two flips are used, it’s reduced by half. If three flips are used it’s reduced by 66% and so on.
In this illustration, the stereo pair (top) and interlaced into a single