F.A.Q.

The technique I use is that of lenticular arrays. This is a medium made up of a multitude of cylindrical micro-lenses that act as an “optical selector” to display different images depending on the viewing angle.

In everyday language, my clients mainly use the term hologram...
which I have ultimately adopted.

It is a plastic material: PET, PET-G or acrylic.

The thickness and resolution of the lenses depend on both:

• the desired effect and format,
• the type of printing used.

From a postage stamp (or even smaller) up to 120 cm wide x 200 cm high.
To produce larger formats, several panels need to be printed.

Whatever the format, the prints can be cut to any desired shape .

THE BACK

By default, the back of the print is a flat white that can then have the following finishes:

• Mounting of a 250 g paper with custom printing (e.g. postcard).
• Application of a double-sided adhesive to obtain a self-adhesive label (e.g. sticker).

CUTTING

Cutting can be done:

• by laser.
• with a paper cutter (straight cut).
• or with a custom die-cut shape, notably to obtain rounded corners.

MOUNTING ONTO A PAPER DOCUMENT

A frequent application consists of mounting the hologram onto the cover of a paper document,
typically a 4-page 350 g brochure (e.g. greeting card).

UV digital printing for small quantities and UV offset printing for large quantities.

A series of images is needed, so at least two.
The basic effect of switching between two images is called a “flip”, perfect for illustrating a change of state:

• Day / Night
• Before / After
• For men / For women

To illustrate a mechanism or give a sense of movement, it is better to use 3 views, or 4, or even 5.
Finally, to obtain a continuous animation, it is possible to include around thirty.

Tip: how to turn a 2-view flip effect into an animation .

A simple 2-view flip effect can be enriched by creating a transition between the two images:

• Either by creating a morphing if the subject lends itself to it.
• Or by adding effects (zooms, movements, rotations) to certain elements of the image (texts, illustrations).
  Examples: invitation card - greeting card

NOTE: for large formats intended for display, it is often preferable to limit yourself to 3 or 4 views.

A very specific series of images is needed...
a horizontal tracking shot of the scene or object you want to see in 3D.

There are three ways to create such a series depending on the nature of the visual:

1. For a computer-generated image from 3D software, you simply need to move the virtual camera horizontally.
   Examples: AKKA Technologies - Lumiscaphe - R.T.E.
   
2. For real photography, you should move the camera along a horizontal rail.
   Examples: Laziz HAMANI - The Thinker by RODIN - S.F.A.
3. For an existing image, a 3D conversion must be carried out.
   Examples: The Kiss by RODIN - Vertumnus by ARCIMBOLDO - Laura Palmer

1. THE DESIGN

Specific criteria need to be taken into account apart from the intrinsic quality of the visual.

For a 3D hologram
It is wise to include elements that already provide depth cues: depth of field, perspective, elements placed one in front of another... These monoscopic cues will add to the stereoscopy, to the great delight of our brain.

For an animated hologram
It is lots of small details that make a good animation!
An example: for an image change on a face, it is best to position the eyes precisely at the same place on the different views.

Don't hesitate to involve us as early as possible in the creative process so that we can advise you to achieve the best possible effect.

2. PRINTING

Whether digital or offset, the printing must be flawless:

• Very high resolution.
• Very low dot gain.
• Perfect color alignment.
• Perfect alignment of the print with the lenses.
• Adherent and durable UV inks.

3. THE LENTICULAR ARRAY

The material, focal length, field angle and thickness must be suited to the effect, format and printing.
Transparency and the “resolving power of the lenses” are also criteria to take into account.
As with any product, there are different qualities...

The optical lenses of a lenticular array are cylindrical, unlike the spherical lenses we are used to. As a result, their orientation has to be considered and will depend on the effect and the application.

1. 3D HOLOGRAM

For a 3D hologram, the lenses are always vertical.
In this position our two eyes perceive different images (“interlaced” behind each lens), enabling stereoscopic vision.

2. ANIMATED HOLOGRAM

For an animated hologram, the lenses can be vertical or horizontal.

Vertical lenses

The lenses will be vertical if the print is to be displayed and the animation visible when the observer moves in front of it.
In this case it is preferable to limit the image change to 2 or 3 views.

Horizontal lenses

The lenses will be horizontal for a hand-held print. The animation will then be visible when the observer tilts the print from top to bottom. The animation can then contain up to 32 views.

Special case

In very specific cases it can be worthwhile to tilt the lenses at 30 or 45 degrees to get a mix of both options. This was the case for the book cover of the painter and illustrator Seth.

The notion of focal distance is a setting to take into account for large-format prints.
It is the distance between the print and the observer at which the effect will be optimal.
This distance is set as desired at the time of printing.
The client must inform us of the viewing conditions: at what average distance the observers will be.

When the observer is at the focal distance:
The effect is then optimal and the image change is very fast.

When the observer is closer to the print:
The transition takes place with a wipe effect that follows the observer's movement.

When the observer is farther from the print:
The transition takes place with a wipe effect in the direction opposite to the observer's movement.

NOTE:
For small formats held in the hand, the focal distance is always set at about thirty centimeters.