FAQs
Silver Halide
This is a photographic type material, similar to conventional black and white photo- graphic film but with a very high silver content. When processed the film is virtually transparent. Though it can be used in a mass reproduction process, it is normally re- served for display holograms.
The film is sensitive to red laser light, usually from a Helium Neon, Krypton or Ruby Pulse laser. The material comes as either film or glass plates.
Plates are more expensive than film. The material is processed in a similar way to photographic film, via a special developer and bleach. Mass reproduction of silver halide holograms is now limited to 10" X 8."
Photopolymer has largely taken over this medium for replication work (see later). Silver Halide is ideal for large display transmission holograms. The largest size of film available is 1m X 10m. Multicolored and full, true colour transmission holograms are possible. These make the separate "rainbows" overlap causing colour mixing or areas of distinct colours. It is generally simpler to make large transmission holograms than large reflection holograms.
Ideally, a silver halide transmission display hologram should be lit from behind. With the right type of imagery, some beautiful effects can be achieved.
