Considerations on new primaries for high definition television

A constant-luminance-coding (CIELAB) codec is presented for high-definition TV (HDTV) use that offers the possibility of enlarging the reproducible color TV spectrum by selecting a new set of primary colors. Tests on a BBC standard color card showed that this type of processing gives full flexibility for the choice of receiver and camera primaries and transparency for the transmission of all real surface colors. Subjective tests were carried out to investigate the importance of a wider color spectrum and the acceptability of CIELAB coding in a compatible HD-MAC system. It was found that more saturated primaries help to minimize calorimetric distortions if CIELAB coded signals are decoded by a conventional decoder.