Natural pigment (5)
(Other definitions for ochre that I've seen before include "Yellowish-orange colour" , "Earthy colour" , "Pale brownish-yellow colour or pigment" , "Red or yellow pigment" , "Light yellow-brown colour" .)
'natural pigment' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for umber that I've seen before include "Dark brown (pigment)" , "Yellowish-brown pigment" , "Dark brown coloring matter" , "Natural colouring matter, dark brown" , "Usually dark brown mineral" .)