Anaglyphs are generally recognized as the easiest way to view printed stereo pairs. But, they are not the only one. And not even the best. There are, for instance, techniques that are based on glasses with polarized lenses which are generally adopted for the projection of stereo images and videos; or, for the home users, there are glasses (called shutter LCD) with lenses electronically opened and closed in synch (left lens open with right closed and viceversa). The apex are then the 3D helmets which, however, still suffer of a few limitations in the technology and, above all, in the costs.

In the paragraphs of this section we point our attention to some techniques, called Free-Viewing, that, even if don't require any viewer, need a kind of training of the ocular muscles and show, therefore, some troubles mostly at the beginning.

Loreo trades some viewers, for cross and parallel stereo couples, at a low cost and undoubted effectiveness; we believed to be useful to spend a few words also about these.

At last, the dream of every expert in Stereoscopy is the possibility to let anyone appreciate the depth of a scene without the need of viewers or ocular techniques: lenticulars go in this direction even if they present many difficulties in the realization.