The scarcity of color-names found in the Bible and other ancient literatures has been differently accounted for by various scholars. All that can with certainty be said of the ancients in this respect is that their color vocabulary was undeveloped.
To the psychological reasons for such an undeveloped state among all nations of antiquity (compare Wundt, "Völkerpsychologie: Die Sprache," ii. 513, 514) was added, in the case of the Israelites, the religious prohibition of idolatry at a period of history when painting, like other arts, was largely, if not altogether, in the service of idolatry. Needlework in colors, as well as dyed stuffs, was indeed known in Israel in very early times, but the coloring was in all probability of a simple kind.
That provides a significant contrast to the ideas mentioned in my original color post, from which one could conclude that the lack of color names pointed to lack of progress in a society.
In the section "Degrees of Darkness", the article gives the following explanation for chum חום:
"hum" (literally, "hot," then "dark," "brown") is used of the wool of sheep (Gen. xxx. 32 and passim).
The text quoted here is the story where Yaakov claims from Lavan the chum colored sheep.
Klein provides a similar etymology:
Probably from חום (= to be warm), which is related to חמם, hence lit. meaning 'resembling in color to something burned'.
However, there is a debate amongst the commentaries as to the identity of the chum referred to in Bereshit 30. Rashi says chum means ros, similar to red. Rav Saadia Gaon, Ibn Ezra and Radak (quoting Arabic) identify chum with shachor, black. Ramban agrees with Rashi, saying that if Yaakov had claimed the black sheep, Lavan would not have agreed, for this is a very common color for sheep. (Kaddari quotes Ludwig Koehler as saying that chum might not be a color at all, but meant "in heat" - מיוחם meyucham.)
Well, how do we resolve this disagreement in the Rishonim? And from where do we get the color brown, if the opinions presented are red and black? Split the difference. Even-Shoshan in his Concordance, translates chum as "reddish-black" and Kaddari suggests "red and black?".