
Concerning Pointer, see the
marginal note on page 255.
Eq 26.8
CBC R components for Rec. 1361 HDTV
One method of extending the color gamut of an R'G'B'
system is to allow components to excurse below zero
and above unity. In
Rec. 1361 trans~er~unction, on
page 265, I explained one approach. Rec. 1361 is based
upon Rec. 709 primaries, but enables the
RGB tristim-
ulus components to excurse from -1/4 to +4/3.
When transformed to Rec. 709 Y'CBC R, all of the real
surface colors documented by Pointer- that is, all the
colors in Pointer's gamut- produce values that are
Y'CBCR-Valid. Though Rec. 1361 was needed ...