Masks are not the faces but faces wear the masks. So sometimes they are the manifestations of one's mood and nature and sometimes not.
We try to conceal our emotions and we become successful. Then we wear face masks. So they are truly relative.

I work on faces.Sometimes they are reflective of his mood,then the masks they wear are relective of emotions.

I colour and play with the emotions by different masks. Colours are also relative.
Suppose a colour green is favoured by a boy of 10 year's old and when he grows his choice changes.

In his twenties he likes brown and his thirties he likes red.
So the true spirit of colour changes with the face and also with the masks.

Thus what is hidden sometimes get exposed and what is exposed those need the colourful masks to hide.