From there the interlaced image can be printed directly to the back (smooth side) of the lens or it can be printed to a substrate (ideally a synthetic paper) and laminated to the lens. When printing to the backside of the lens, the critical registration of the fine "slices" of interlaced images must be absolutely correct during the lithographic or screen printing process or "ghosting" and poor imagery might result.
The combined lenticular print will show two or more different images simply by changing the angle from which the print is viewed. If more (30+) images are used, taken in a sequence, one can even show a short video of about one second. Though normally produced in sheet form, by interlacing simple images or different colors throughout the artwork, lenticular images can also be created in roll form with 3D effects or multi-color changes. Alternatively, one can use several images of the same object, taken from slightly different angles, and then create a lenticular print which shows a stereoscopic 3D effect. 3D effects can only be achieved in a side to side (left to right) direction, as the viewer's left eye needs to be seeing from a slightly different angle than the right to achieve the stereoscopic effect. Other effects, like morphs, motion, and zooms work better (less ghosting or latent effects) as top-to-bottom effects, but can be achieved in both directions.
There are several film processors that will take two or more pictures and create lenticular prints for hobbyists, at a reasonable cost. For slightly more money one can buy the equipment to make lenticular prints at home. This is in addition to the many corporate services that provide high volume lenticular printing.
There are many commercial end uses for lenticular images, which can made from PVC, APET, acrylic, and PETG, as well as other materials. While PETG and APET are the most common, other materials are becoming popular to accommodate outdoor use and special forming due to the increasing use of lenticular images on cups and gift cards. Lithographic lenticular printing allows for the flat side of the lenticular sheet to have ink placed directly onto the lens, while high-resolution photographic lenticulars typically have the image laminated to the lens.
Recently, large format (over 2 m) lenticular images have been used in bus shelters and movie theaters. These are printed using an oversized lithographic press. Many advances have been made to the extrusion of lenticular lens and the way it is printed which has led to a decrease in cost and an increase in quality. Lenticular images have recently seen a surge in activity, from gracing the cover of the May 2006 issue of Rolling Stone to trading cards, sports posters and signs in stores that help to attract buyers.
The end result is that a single eye or camera looking at the print sees a single whole image, but an eye or camera with a different angle of view will see a different image.
Lenticular images were popularized from the late 1940s to the mid 1980's by the Vari-Vue company. Early products included animated political campaign badges with the slogan "I Like Ike!" and animated cards that were stuck on boxes of Cheerios. By the late sixties the company marketed about two thousand stock products including twelve inch square moving pattern and color sheets, large images (many religious), and a huge range of novelties including badges. The badge products included the Rolling Stones' tongue logo and an early Beatles badge with pictures of the 'fab four' on a red background.
Some notable lenticular prints from this time include the limited-edition cover of the Rolling Stones' Their Satanic Majesties Request, and Saturnalia's Magical Love, a picture disk with a lenticular center. Several magazines including Look and Venture published issues in the 1960s that contained lenticular images. Many of the magazine images were produced by Crowle Communications (also known as Visual Panographics). Images produced by the company ranged from just a few millimeters to 28 by 19.5 inches. The panoramic cameras used for most of the early lenticular prints were French-made and weighed about 300 pounds. In the 1930s they were known as "auto-stereo cameras". These wood and brass cameras had a motorized lens that moved in a semicircle around the lens's nodal point. Sheet transparency film with the lenticular lens overlay was loaded into special dark slides (about 10×15 inches) and these were then inserted into the camera. The exposure time was several seconds long, giving time for the motor drive to power the lens around in an arc.
A related product produced by a small company in New Jersey was Rowlux. Unlike the Vari-Vue product, Rowlux used a microprismatic lens structure made by a process they patented in 1972, and no paper print. Instead the plastic (Polycarbonate, flexible PVC and later PETG) was dyed with translucent colors and the film was usually thin and flexible (from 0.002" in thickness).
While not a true lenticular, the Dufex Process (Manufactured by F.J. Warren Ltd.) does use a form of lens structure to animate the image. The process consists of a metallic foil imprinted by litho printing with the image. The foil is than laminated to a thin sheet of card stock that has had a thick layer of wax coated upon it. The heated lamination press has the Dufex embossing plate on its upper platen. The plate has been engraved with angled 'lenses' at different angles so designed as to match the artwork and reflect light at different intensities depending on angle of view.
Typically, ultraviolet-cured inks are used. These dry very quickly by direct conversion of the liquid ink to a solid form, rather than by evaporation of liquid solvents from a mixture. Powerful (400W per sq. in) ultraviolet (UV) lamps are used to rapidly cure the ink. This allows lenticular images to be printed at high speed.
Free radicals from photoinitiators initiate the reaction of polymerization of monomers and prepolymers. The polymerization reaction then spreads, gradually increasing the size of the macromolecules and therefore the viscosity, which solidifies the ink film.
Relatively few compounds are suitable for use in printing inks, because many suitable candidates are toxic, volatile, or smell bad. A working group consisting of HSE (Health and Safety Executive—England), BG (Berufsgenossenschaften-Germany) and the CNAMTS (Caisse Nationale d'Assurance Maladie des Travailleurs Salariés) is studying UV printing and working on the classification of components not yet included in the European directives.
Lithographic printing relies on the surface tension of the water and interfacial tension. The repulsion between the oil-based ink and the water ensures that the ink ends up where it should on the plate. The greater the interfacial tension, the less the ink and water mix and the less chance there is of forming an emulsion (mixture of ink and water). Increased surface tension of the solution causes water to run well on the plate, forming a continuous thin film.
The electrical conductivity of the solution is measured to determine the amount of additives required.
There are many types of UV curing systems, but mercury vapor lamps are the most common. These lamps emit UV radiation in a broad spectrum and provide optimum curing. The UV sources typically generate 160–200 W/cm of radiation.
This poor marking is shown by doubling of the visual; a lack of clarity; a streak of colour or wavy colours (especially for four-colour shades) during a change of phase by inclination of the visual.Synchronisation of parallelism of the printing to the lenticules: The origin of this problem is a fault in the printing and forcibly generates a phase defect. The passage from one visual to another must be simultaneous over the entire format. But when this problem occurs, there is a lag in the effects on the diagonals. At the end of one diagonal of the visual, we have one effect, and at the other end we have another.Phasing: In most cases, the problem comes from imprecise cutting of the material, as explained below. Nevertheless, poor printing and rectification conditions may also be behind it.
In theory, for a given angle of observation, one and the same visual must appear, for the entire batch. As a general rule, the angle of vision is around 45°, and this angle must be in agreement with the sequence provided by the master. If the images have a tendency to double perpendicularly (for 3-D) or if the images provided for observation to the left appear to the right (top/bottom), there is a phasing problem.
Two examples, taken from the same production batch:
The first image shows a cut which removed about 150 µm of the first lens, and which shows irregular cutting of the lenticular lenses. The second image shows a cut which removed about 30 µm of the first lens. Defects in cutting such as these lead to a serious phase problem. In the printing press the image being printed is aligned relative to the edges of the sheet of material. If the sheet is not always cut in the same place relative to the first lenticule, a phase error is introduced between the lenses and the image slices.
Wipo Publishes Patent of Henkel and Anshyang Albert Lin for "Lenticular Print Three Dimensional Image Display Device and Method of Fabricing the Same" (American Inventor)
Apr 06, 2013; GENEVA, April 6 -- Publication No. WO/2013/048615 was published on April 4.Title of the invention: "LENTICULAR PRINT THREE...