I have a friend that is an iconographer and he says just the opposite. Red is the color for divinity and blue is the color of humanity. If you notice, on some icons of Christ, his inner clothing is red and his outer clothing is blue. On icons of the Theotokos, it is in the opposite order. Her inner clothing is blue, and her outer clothing is red.
Second this. However, I think there's room for interpretation, as long as your theology is correct.
The Theotokos' inner blue garment represents that in essence she is earthborn, but she has put on the Divine Glory over it. Christ's inner red garment represents His Divinity, and then He put on the human nature over it.
In the Russian tradition especially, it would make more sense for red to mean the Divine Glory, since red is such an auspicious color in Russian iconography.