To highlight the element of wealth and nobility* in the woman which, when freed from evil spirits , followed and supported materially Jesus throughout His teaching. Maria Magdalene came  along with other women (named Holy Myrrh-bearers in the Orthodox Church),. They risked and eventually gave everything for Him. They were rewarded by being the first to witness His resurrection.

So I believe that is the same element we highlight by painting martyrs’ garments in red; color. We are picturing nobility, that in this case is acquired not by heritage but by their virtues and their suffering.

This Mary Magdalene Red could also be  Porpura.  The Greek Porphyra, also referred to as * Tyrian red or “Tyrian purple”  (source Wikipedia). In antiquity  -and until the first fall of Constantinople in 1204– purple was made by an extravagantly expensive dye. For that purposeit was reserved as a color only for the garments of the Emperors and of the very- very rich. Now in art, Tyrian purple can be interpreted in many ways.  Usually pictured as a very rich color  it ranges from a bluish purple- to lushius dried blood red and is is obsiously displaying wealth and authority.

For more on colors you may also see my other post: https://angelicon.gr/silk-effect-color-layers-in-egg-tempera/