I sent a note to Mark Keriotis, the developer of A Brief Guide to Byzantine Icons, and he was kind enough to respond with some information on the symbolism of color in Icons. Here is what he sent me from a book called The Icon: Image of the Invisible By Egon Sendler.

White

The color "closest to light itself" (Sendler p153) It symbolizes Divinity, purity, innocence, death to sin.
Examples: The Transfiguration, the Resurrection

Yellow or Gold

Also suggests Light, but in a manner that is more regal and powerful but not quite as gentle as White. It emphasizes the Kingdom of Heaven with its Eternal Space and Time.
Examples: Common background color, Halos

Blue

"The least sensual of colors," it symbolizes the intangible qualities of the spiritual, tranquility, and Heaven. It is also strongly associated with virginity.
Examples: Common background color, mandorlae

Red

"The most active of colors" it can represent the blood of Life, or the Divine radiant fire which consumes evil yet sustains goodness.
Examples: Blood, Last judgment, Elijah's chariot, the Burning Bush

Purple

Reserved in the ancient world for the wealthy, it implies "Royal and Priestly" power and dignity.
Examples: The Bridegroom, The Virgin's cloak

Green

Indicates growth and young energy having the calmness of Blue and the energy of Red. It is strongly associated with the Holy Spirit.
Examples: Prophet's robes

Brown

Not readily meaningful apart from the way "it reflects the density of matter" but is more lively than Black.
Examples: most buildings and inanimate objects

Black

The absence of light, it is reserved for depicting the darkness of sin and death.
Examples: The Nativity Cave, Pit of Hades, tombs

I gave Mark a link to this thread. Perhaps he will drop in and add his considerable knowledge to the discussion.

      - Mark