Hologram and Holography - Holograms Versus Photographs

Ordinary photography only accounts for the intensity of light. The only consideration is whether or not the light is too bright. You can usually see the grains in a photographic image, but the features in the fringe pattern of a hologram measure the same as each wavelength of light (1/2000 of a millimeter), recording amplitude in their depth of modulation and phase in their varying positions.

Older "3-D" imagery constructed from photographs is known as stereoscopy. This method reproduces a single viewpoint with the aid of two images. The two are superposed to recreate the parallax between your left eye's view and your right eye's view, but that is where your options stop. Holography allows for a full range of parallax effects: you can see around, over and even behind objects in a hologram.

Flashbulbs can be uncomfortable, but holograms use laser technology. Direct physical contact with a low-power laser cannot harm you unless you look directly into the beam, but remove all potentially reflective surfaces from the area, in order to prevent an accident.