Dye, pigment (6)
I believe the answer is:
colour
I believe this is a double definition.
'dye' is the first definition.
(I know that dye can be written as colour)
'pigment' is the second definition.
(I know that pigment can be written as colour)
(Other definitions for colour that I've seen before include "Tinge - distort" , "Hue, tint" , "See 10" , "Distort; blush; hue" , "Pigment, paint or dye" .)