Painter maybe backing himself - it's about time (6)
I believe the answer is:
artist
'painter maybe' is the definition.
(I know that painter is a type of artist)
'backing himself it's about time' is the wordplay.
'backing' says the letters should be written in reverse.
'himself' becomes 'ra' (I can't explain this - if you can you should believe this answer much more).
'about' indicates anagramming the letters.
'time' becomes 't' (abbreviation).
'ra' written backwards gives 'ar'.
'its' with letters rearranged gives 'tis'.
'ar'+'tis'+'t'='ARTIST'
(Other definitions for artist that I've seen before include "Painter, sculptor etc" , "Creative individual" , "Creative or skilful person" , "Model employer, perhaps" , "Rousseau perhaps" .)