An in-depth apparent three-dimensional image with great realism produced by illuminating an object field with two interrelated coherent lightbeams, one directly from a coherent light source and the other slightly delayed, thus giving the three-dimensional appearance. Note: The image can be recorded and recreated using similar techniques. Damage to a spot on the holographic film results only in a slight reduction in resolution or brightness, not a loss of a picture element that would show up as a spot, a smudge, or a damaged area. A scanning technique permits recording on film, which can later be recovered and displayed. The recording is rendered intelligible only by reversing the holographic process. See also  coherence,  coherency,  coherent,  coherent light,  illumination,  image,  light,  lightbeam,  light source,  object,  picture element,  process,  recording,  resolution,  scanning,  virtual reality,  virtual reality deck,  virtual reality system.