The position of a wave in space, measured at a particular point in time. The portion of a laser beam that goes directly to the holographic film. The interference pattern that results from the object beam meeting the reference beam at the holographic film is recorded on the film. Reflection holograms are lit from the front, reflecting the light to the viewer. Transmission holograms are lit from behind, bending the light as it passes through the hologram to your eyes.
White light is incoherent, while laser light is coherent.
A white light transmission hologram, or rainbow hologram, is one which can be displayed using ordinary white light. Early holograms required viewing with coherent laser light.