It all starts with a plan

There are many approaches to creating effective lenticular work and it can start with something as simple as choosing two of your favorite photos. But lenticular can do much more, including impressive illusions of dimensionality, animation and optical effects. Parallax Printing will assist you in matching your goals with the right approach and help optimize your artwork for maximum effect.

FLIP LENTICULAR (2 PHASE AND MULTI-PHASE)
90% of all lenticulars are made using no more than 2 or 3 frames for effect. It's often a before/after, with/without or a short narrative sequence. It can be an incredibly effective approach and has the added advantage of being easy to set up. Additional frames can be used too, but more than a few frames can sometimes muddy the result. While many flip lenticulars work as expected there are a few things that are helpful to consider at the design stage if you have the option.

1. Number of Frames. The rule here is to use the least amount of frames required to portray the effect. In general smaller pieces should use fewer frames because they typically require a finer lenticular lens with limited capacity while larger pieces can often use up to 5 frames with good results. The more frames you have the quicker the lenticular flips and the more neighboring images will bleed through. As with many things “less is more” is often a good strategy.

2. Looping. If you have a flip sequence with 3 or more frames where there is a visual progression to the images you might consider making a looping sequence. If you portray a person jumping in the air over 4 frames a viewer walking by will see this repeat several times like this: 1,2,3,4,1,2,3,4 etc. There is a hard shift from frame 4 back to frame 1 each time, the jumping person will be in the air and suddenly back on the ground. But if the image sequence is made into a loop like 1,2,3,4,3,2 it will show the person jumping up and falling back down in a smooth motion. This is not necessary or always relevant but it can be very effective in the right circumstances.

3. Ghosting. Bleed through from neighboring images is known as ghosting and happens when a lenticular has a frame with flat areas of light color (or white) and a neighboring frame with a dark object. Flat areas of light color simply cannot hide things very well and it is common to see neighboring areas show through in these frames between 2-10%. It is much better to have white text on a black background than black text on a white background, for example, and colored text on a photographic background is better still. Lenticulars with photographic content or active patterns in all frames tend to fare best in controlling ghosting. The overall degree to which it is considered a problem depends greatly on the intentions of the designer and some people even work with it as a creative variable. In general Lower LPI lenses tend to handle ghosting better (discussed in the PRINTING section) though they are meant for larger prints because of the coarser surface. 

4. Banding. Ideally a flip from one color to another would happen instantaneously or as a clean gradient but sometimes there can appear subtle vertical bands across the surface of the print. These result from the mathematical impossibility of getting evenly divisible numbers between the printer and the fractional LPI of the lens. Banding only happens in the transitions of the piece not in the individual frames and is typically subtle, but for pieces where the color transition is an important feature of the work or for flips between high contrast solid colors it may present as an issue. The solutions are to avoid flipping between images with solid areas of different colors or try to minimize the issue by choosing colors with similar values. Photographic content is almost never subject to banding issues, so consider a photo background instead of flat colors if your design allows for it.

ANIMATION
Animated lenticulars are essentially flip lenticulars with less image-to-image change and more frames. As many as 30 frames can be used under the right circumstances, but it is often common to use 15 or fewer. Animations can be built by hand or they can be taken from high resolution video sources using every X frame or other selective measure. Animated lenticulars are good at portraying a feeling of movement or change and can be very fluid but it is sometimes difficult to freeze any single frame which can contribute to a sense of blurriness or impermanence.

3D
Creating flat prints that have an illusion of dimensionality is one of lenticular’s best tricks. It does this by giving our left and right eyes slightly different versions of an image in a way that imitates stereoscopic vision. To work a 3D lenticular uses a sequence of images that have small horizontal changes and selectively pulls from this image sequence depending on your position to the print. Creating a 3D image sequence can be your responsibility or ours. There are two basic methods for approaching 3D lenticular.

1. Shoot a stationary subject using a camera on a slider. We offer a tutorial on the subject here but the basic principle is to pass a camera in front of a subject in such a way that when the photos are later aligned in Photoshop and played as an animation objects in the background move to the right and objects in the foreground move to the left. This same principle can be used for a camera in the analogue world or for a virtual camera in a 3D modeling environment.

2. Create 3D from a 2D image. A simple and common application of this method uses a flat photo on one level and an object/text on a second level so that there appears to be dimensional space between the two. Variations on this approach can include Photoshop files with a hundred or more layers, each assigned to a distinct location in 3D space. The most sophisticated variant of this method uses Photoshop layers + grayscale depth maps to warp the layers and provide a sense of volume so that things appear natural and not like a cutout cardboard diorama. When creating artwork that will be converted to 3D you can do as little or as much as you like in advance and we will take it from there. You can provide a single 2D photograph or a layered Photoshop file with depth maps or even a final rendered image sequence, depending on your level of skill in this area.

4D
The combining of Flip/Animation and 3D is known as 4D. Some implementations of 4D are fairly straight forward like adding a flip element that turns on and off to a 3D lenticular or having a subject in a 3D photoshoot move several times during the image capture sequence. Other approaches require more planning and deeper digital workflows. One downside to 4D is that it cannot be looped seamlessly because 3D always has a reset point, and that a lens must be chosen that prioritizes either 3D or Flip qualities.

RESOLUTION
There are two kinds of resolution to consider, one is the pixel count of the source files and the other is the lenticule count of the lenticular lens. The pixel count of lenticulars can often be quite low and yield good results because the final print is a composite of multiple images. We suggest 150 DPI for most files but we routinely work with files of even lower resolution.

Lens resolution, measured in lenticules per inch (LPI) is how fine the surface of the lenticular plastic appears. In a perfect world a very fine lens would be chosen for every project but while finer lenses are good for preserving small details for things like thin lines and small text they are more prone to ghosting and can handle fewer frames. In general small pieces with fine details push images towards fine lens while larger pieces with high contrast or multiple images push towards coarse lens. The reason to choose one lens over another is often complicated by multiple competing factors and frequently requires one concern to be prioritized. Lens resolution is often a decision made by the printer though we are happy to accommodate your preferences. More detail on lens resolution can be found in the PRINTING section