Proto-Indo-European probably had
what Berlin and Kay classify as a Stage II color system, which includes only
black, white and red; Berlin and Kay use the term 'row' for red, as the semantic
space occupied by 'red' in such a system is not that you find in larger systems.
'Row' stands for red-yellow.
Homeric Greek would seem to also be
Stage II, or perhaps, transition to Stage III, where either yellow or blue-green
(what Berlin and Kay call 'grue') are added to the system.
Stage IV has both grue and yellow.
Stage V fully discriminates green and blue. Stage VI adds brown. Stage VII adds
pink, purple, orange and gray.
It needs to be noted that different
languages break up color differently. Russian, so I understand, breaks up blue
and green differently than English. Russian blue is not English
blue.
At the earlier stages, the
distinction between black and white also needs to be widened. The
semantic space would seem closer to that conveyed by English 'light' and 'dark'.
After *h1reud, erythros in Greek (which Piotr has
covered), the next IE color term is *ghel, which is ancestral
to the English words yellow, gold. There is also the term
*h1elu, 'dull red'.
Mark Odegard.