Introduction |
| Lenticular Lens | A plastic lens consisting of an array of optical elements called lenticules. When viewed from different angles, different areas under the lens are magnified. |
| Lenticular Image | A specially prepared image to which the lens is attached. Views are arranged under lenticules so that each eye is projected a different view. The brain then processes these views to a single coherent 3D image. |
Lenticular Lens TypesThere are many different types of lenticular lenses. Different lens types are suitable for different applications. Two main parameters differentiate between the different lens types: |
| (Mechanical) Pitch | The exact physical count of lenticules per inch. Pitch value is measured in Lenticules Per Inch (LPI). |
| Viewing angle | Lenses come in different viewing angles. The main distinction is between wide and narrow viewing angled lenses. |
| The thickness is determined by both the pitch and the viewing angle. The lower the pitch, the thicker the lens. The narrower the viewing angle the thicker the lens and the larger the viewing distance for 3D. |
Selecting a Lenticular LensThe following aspects should be considered when selecting a lens: |
| Lens thickness | A distinction is usually made between thick lenses (up to 60 LPI) and thin lenses (60 LPI and above). The lens thickness varies between 150 mil (3.81 mm) to 48 mil (1.22 mm) for thick lenses and from 27 mil (0.686 mm) to 14 mil (0.355 mm) for thin lenses. |
| Different thickness lenses are suitable for different applications. In general, thick lenses are more suitable for printing wide format applications. Thin lenses are more suitable for small, handheld applications and ones with a short viewing distance. |
| The desired effect | Narrow angle lenticular lenses are more suitable for 3D while wide angle lenses are better for flip and animation effects. |
| Printing resolution | The ratio between the printing resolution and the pitch determines the number of views that can be placed under each lenticule. The higher the lens's pitch, the higher the printing resolution required for effective 3D viewing. |
| Viewing distance | The distance from which the picture will be viewed. In general, thick lenses are suitable for medium and long viewing distance applications (e.g. airports, trade shows, malls, POS etc.), and thin lenses are suitable for shorter viewing distances (e.g. handheld items, magazine inserts and packaging, postcards and greeting cards, direct mailing, small posters and promotional items). |
Preparing a Lenticular Image |
| Interlacing | The process of creating a lenticular image from a set of 2D images. Thin strips taken from each of the 2D images are interleaved into one image to match a specific lens pitch. |
| Interlacing the image according to the optical pitch ensures optimal viewing experience. Incorrect optical pitch can introduce blurriness and ineffective 3D viewing. In flip and animated effects an incorrect pitch would result in ghosting. |
| Optical pitch | The mechanical pitch as affected by the viewing distance. |
| Pitch test | A calibration test for determining the pitch of a lens. |
Printing Methods |
| Lenticular printing (directly on lens) | There are two main prerequisites to allow direct printing on the lenticular lens: the printing systems' ability to handle substrates as thick as the lenticular lens and the usage of ink technology that enables the ink to adhere to the plastic and to immediately set on it. The advantage of this method is that it saves the need for lamination (see below). |
| Printing on paper and laminating | When the printing device is incapable of direct lenticular printing on the lens, there is also a possibility of printing on paper and then laminating the paper to the lens. This requires aligning the printed image with the lens, and maintaining the alignment while laminating. |
More about Lenses |
| Durability | The lenticular lens is manufactured from various types of plastic (PETG, PVC, Acrylic). The lens's ability to withstand extreme weather conditions as well as its resistance to vandalism, scratches, breakage and fire depends on the type of plastic from which it is made. |
| Maintenance | As the lenses are made of plastic, they can shrink or expand if affected by changes in humidity or temperature. Therefore, to avoid a change in the pitch of a lens, lenses should be stored in a controlled environment. |
| Cost | The thicker the lens is, the higher its cost will be. There is economic sense in that, as the thick lenses are used for large format, short run application with relatively high profit margins, which justify the high cost of the lens. Smaller jobs that are printed in masses are printed using litho on relatively low cost lenticulars. |
Matching the Image to the Lens |
| Alignment | Adjusting the image to match the lens. Vertical alignment ensures the image strips are parallel to the lenticules, while center alignment ensures best viewing experience by eliminating the 'jump' in the image when viewing it from the center. |
Lenticular Quality parameters |
| A high quality lens is essential for the full impact of the different lenticular effects. There are three main parameters that define high quality material: | Transparency - the material should be as transparent as possible to get a clear image. |
| Pitch Quality - a pitch that is consistent throughout the whole sheet is important to achieve a high quality and consistent image. |
| Edge Cut Consistency - a consistent edge cut enables consistency in the placement of the printed image relative to the lenticules. It is also important to have consistency throughout a whole run - Sheet-to-Sheet. |
Purchasing the Lens |
| Ordering lenses | There are several lenticular manufacturers around the world. HumanEyes has secured special pricing for its customers with some of them. For more information about lenses and lenticular printing, please contact HumanEyes at 3D@humaneyes.com |
| Lenticular lens sheet size | There are standard sizes for lenticular sheets, however for large orders manufacturers may be willing to cut the sheets to a certain size. You should contact the manufacturers directly to further discuss this option. |
| Litho printing | Mainly used for long runs and relatively small format and short viewing distance applications. In this case only economical when printing directly on the lens, eliminating the need for lamination. The thin lenses are suitable both for the limitations of the litho printer and coincide with the applications needs. |
| Wide format digital printing (Inkjet and photographic printers) | Mainly used for short runs, large format and medium to long viewing distance applications. As most digital printers do not have the ability to do direct lenticular printing (on the lens), printing is usually done on high quality paper and then laminated to the lens.
The short runs economically coincide with the necessity in lamination. |
