From BiblePortal Wikipedia

Black [1]

(usually some form of קָדִר , Kadar', to be Dusky, or שָׁחֹר , Shachor', Swarthy; Μέλας ). Although the Orientals do not wear black in mourning, yet, like the ancient Jews, they regard the color as a symbol of affliction, disaster, and privation. In fact, the custom of wearing black in mourning is a sort of visible expression of what is in the East a figure of speech. In Scripture blackness is used as symbolical of afflictions occasioned by drought and famine ( Job 30:30;  Jeremiah 14:2;  Lamentations 4:8;  Lamentations 5:10). Whether this be founded on any notion that the hue of the complexion was deepened by privation has not been ascertained; but it has been remarked by Chardin and others that in the periodical mourning of the Persians for Hossein many of those who take part in the ceremonies appear with their bodies blackened, in order to express the extremity of thirst and heat which Hossein suffered, and which, as is alleged, was so great that he turned black, and the tongue swelled till it protruded from his mouth. In  Malachi 3:14, we read, "What profit is it that we keep his ordinances, and that we have walked in blackness (Auth. Vers. "mournfully") before the Lord of Hosts;" meaning that they had fasted in sackcloth and ashes. "Black" occurs as a symbol of fear in  Joel 2:6 : "All faces shall gather blackness," or darken with apprehension and distress. This use of the word may be paralleled from Virgil (AEn. 9:719; Georg. 4:468). The same expression which Joel uses is employed by Nahum ( Nahum 2:10) to denote the extremity of pain and sorrow. In  Zechariah 6:2-6, four chariots are represented drawn by horses of different colors, which have usually been supposed to denote the four great empires of the world in succession: the Assyrian or Babylonian, the Persian, Grecian, and Roman, distinguishable both by their order and attributes; the black horses in that case seeming to denote the Persian empire, which, by subduing the Chaldaeans, and being about to inflict a second heavy chastisement on Babylon, quieted the spirit of Jehovah ( Zechariah 6:8) with respect to Chaldlea, a country always spoken of as lying to the north of Judaea. But the color here is probably, as elsewhere, only symbolical in general of the utter devastation of Babylon by the Persians (see Henderson, Comment. in loc.). The figure of a man seated on a black horse, with the balance to weigh corn and the other necessaries of life, is employed in  Revelation 6:5 to signify great want and scarcity, threatening the world with famine, a judgment of God next to the sword. Also, 'The sun became black as sackcloth of hair" ( Revelation 6:12) is a figure employed, as some think, to describe the state of the Church during the last and most severe of the persecutions under the heathen Roman empire. Great public calamities are often thus figuratively described by earthquakes, eclipses, and the like, as if the order of nature were inverted. In connection with this subject it may be remarked that black is studiously avoided in dress by all Orientals, except in certain garments of hair or wool, which are naturally of that color. Black is also sometimes imposed as a mark of humiliating distinction by dominant nations upon subject or tributary tribes, the most familiar instance of which is the obligation laid upon the Jews in Turkey of wearing black turbans. (See Color).