Natural Color Holographic Stereograms By Superimposing Three Rainbow Holograms

A single-wavelength laser and a set of color-separated, black-and-white, two-dimensional photographs are used to produce three holographic stereograms, each containing a lightness scale corresponding to an appropriate concentration of the original primary color. The real images are individually projected and exposed onto a single holographic emulsion. This hologram, when reconstructed in white light, produces the overlapping spectra of three rainbow holograms. In image areas of equal density, these superimposed spectra create a shade of gray proportional to their combined intensities. All mixtures of colors and tones are found in other image areas. Detailed studies of the primary-color, viewing zones reveal misalignments and curvatures due to chromatic, spherical aberrations. The resulting color misregistration limits image depth to a few centimeters. However, within a restricted viewing area, three-dimensional images do appear in full natural color.