White light hologram is somewhat different from regular holograms but you need to know the difference only after having an idea about the mechanism of a regular hologram. All you need to know about the functioning of a regular hologram is that two coherent beams are mainly needed for the production of a hologram and one of the beam is called the reference beam and the other one is called the object beam. As the two beams interfere, it gets recorded in the photographic film. And once the film is developed you can get a look of it by illuminating the developed film with a laser film.
Reflection hologram – A type of white light hologram
Regular holograms are therefore only capable of producing sharp images when viewed with a monochromatic light. However, reflection holograms are those which is capable of being viewed in a white light as well as in these type of white light hologram the object and reference beams actually stands on the opposite side of the photographic film. As a result, the plane of the film has the structure of the interference pattern lying perpendicular to it. You can have twenty or more layers within the emulsion, if the thickness is around 15 mm and it will ultimately result to a truly three dimensional recorded pattern. This developed film is illuminated with a white light beam which makes the hologram an automated selector of proper wavelength and that too for each angle of incidence. This ultimately makes a hologram, which you can view with white light from a point source.
Rainbow hologram involves a two stage process
The rainbow hologram is another type of white light hologram. Steven Benton Invented the hologram, which can be viewed even with the help of a transmitted light of an incandescent lamp. This hologram makes the phenomenon happen by a simple two stage process with the first step involving making of a transmission hologram. Then it involves construction of another hologram by treating the first image of the hologram as the object.