A three-dimensional image created by holography. It is not obtained by focusing light on an image converter (photographic film, optical sensor) through a lens. Rather, the interference image is recorded that results from interaction of the light reflected from the object to be imaged with a reference beam of the light source. This method demands extremely coherent light (i.e. synchronously oscillating light), such as that generated by a laser. Strictly speaking, viewing also requires coherent light on which the hologram superimposes the same interference image that it was produced with. If you make concessions as regards the accuracy of detail, holograms can also be viewed in normal light, in which case direct light produces better results than indirect light.