Color management of four-primary digital light processing projectors

Abstract

Traditionally, hardware for additive color displays, including projection devices, has been built from a set of only three prima-ries: a red, a green, and a blue. Recently, some manufacturers of projector displays have designed their hardware to project a fourth primary, a white. This fourth primary has been helpful in increasing the luminous output possible from these displays. Because interde-vice color communication infrastructure is based on red, green, and blue channels (RGB), the four- primary devices accept RGB digits and internally convert to red, green, blue, and white channels (RGBW). From a color management viewpoint, the four- color projectors look like RGB devices, but the typical color characterization models fail owing to the complexity introduced by the hidden RGB to RGBW conversion. Several four- primary digital light processing projectors were investigated and a new characterization model is proposed that approximately accounts for the relationship between RGB digital counts and resultant projected colorimetry.