::Types of holograms
Transmission Holograms: Viewable with laser light. They are made with both beams approaching the film from the SAME side.
Reflection (White Light) Holograms: Viewable with white light from a suitable source such as spotlight, flashlight, the sun, etc. They are made with the two beams approaching the holographic film from OPPOSITE sides.
Multiple channel holograms: Two or more images are visible from different angles. There are different types of multiple channel holograms:
Simple ones with 2, 3, or a few images each viewed from a different angle.
Multiplex: A large number of "flat" pictures of a subject viewed from different angles are combined into a single, 3-dimensional image of the object. A COMPOSED hologram.
Rainbow holograms: The same image appears in a different color when viewed from different angles.
Real Image Holograms (H-2's)
These are usually reflection holograms made from a transmission original (H-1). The image dramatically projects IN FRONT OF THE PLATE toward the viewer. Most holograms in holography museums are of this type. The procedure for making them is quite elaborate and demands precise control of angles.
Mass-Produced Holograms
Embossed--Made by stamping on foiled backed mylar film using a metal master (most common method).
Polymer--Made from light sensitive plastic. The Polaroid Corporation mass produces holograms by this method.
Dichromates--Very vivid holograms on jewelry, watches, etc. They are recorded on a light sensitive coating of gel that contains dichromate.