In Byzantium, the royal color of the Empress was blue. Thereafter, the Mother of God was portrayed often wearing blue.
Purple was the royal colour in Byzantium and also the royalty wore red shoes as depicted in some icons.
The "vibrant colours" that Rose was referring to are symbpolic.
For example, in the 2 icons of Christ and His mother in the first row of the iconostasis.
Christ wears a red garment because here red symbolized his divinity and a blue cloak because here blue sybolizes humanity. The message is that Jesus the Divine (the red garment) put on humanity (the blue cloak).
With the Mother of God, the colours are the opposite: She is wearing a blue garment to symbolize her humanity and she puts on a red cloak with symbolizes her taking on Christ, the Divine One in her womb,
I recommend reading Ouspensky's "The Meaning of Icons."
You will find Icons of the Mother of God with lighter blue garments creeping into Ukraine in the 17th century and from ther north to Russia.