Title: Colors B Matrix

Source: Ekman (1963)

Description: Preliminary (non-symmetrized) B matrix based on Colors
data set. Six monochromatic lights of equal brightness served as
stimuli. Their wavelengths were 593, 600, 610, 628, 651, and 674 nm,
i.e., the lights were in the red-yellow range. All possible pairs of
lights were projected onto a screen, and ten subjects were asked for
"contained-in" judgments on each pair.