We are all familiar with the traditional monochromatic reflection hologram, which the invention of the laser made practical. Many will also be familiar with the 3D photographic reality of true colour holography achieved using red green and blue lasers together. Bridging the gap between these two processes is the pseudo colour reflection hologram. This uses a modification of the monochromatic process to achieve full colour but with much greater artistic input and control over the final result.
Essentially a pseudo colour reflection hologram contains two or more individually created single colour holographic images, all recorded using one laser of a particular wavelength. Together these form a full or multi colour image. Each colour element is shot separately, and from an optical point of view can be considered as a completely unique hologram. The desired colours are created by swelling the emulsion, in this case silver bromide, by a carefully controlled amount prior to each exposure. Up to four exposures for different colours can be satisfactorily recorded onto one silver bromide plate, but it is normally two or three.
