Holography is three-dimensional laser photography that appear to have depth. The hologram is a true, three-dimensional record of the original object. The hologram gives different view of the image from different angles with different lights.
The word, hologram is composed of the Greek terms, "holos" for "whole view"; and gram, meaning "written". A hologram is a three-dimensional record of the positive interference of laser light waves. A technical term for holography is wavefront reconstruction. In holography, we record the positive interference of matching wavefronts of laser light. This three-dimensional record is formed as a diffraction pattern; a series of very fine lines, or concentric circles. This diffraction grating bends the viewing light back onto the path of the original recording wavefronts of laser light. The three-dimensional version of the object - the hologram - is reconstructed as light.
A Hologram is the culmination of several process involving physical, chemical and artistic inputs. Hologram is printed onto a set of ultra-thin curved silver plates, which are made to diffract light. When the beam hits the silver plate, the reflections diffract into each specific color, creating two offset images made up of combination of colors that reflect the image of original object. This results in formation of 3D images that are known as Holograms.
It basically comprises of interference patterns between the two images.
The very concept of Holograms has emerged from the need to have a mark of authentication that is simple enough to be identified by even an untrained or illiterate eye, and yet sophisticated enough to make it near impossible to be duplicated or replicated. The extremely high level of technology that goes into its manufacture coupled with the exclusivity of the technology makes it far beyond the reach of a counterfeiter.