When nature contains a way of changing colour (5)
I believe the answer is:
henna
'colour' is the definition.
(I know that henna is a more specific form of the action the tinct)
'when nature contains' is the wordplay.
'contains' says the answer is hidden in the clue.
'HENNA' is hidden in the letters of 'when nature'.
'a way of changing' acts as a link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for henna that I've seen before include "Pigment used on skin" , "natural colour?" , "hair colouring" , "Hair/skin dye" , "shock treatment" .)