Neutral tone (4)
'neutral tone' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ecru that I've seen before include "Raw linen colour" , "Very light brown colour" , "Natural stuff" , "Find a cure, strangely, in the colour" , "Greyish white" .)
(Other definitions for taupe that I've seen before include "Brownish-grey colour" , "shade" , "Fifty Shades of Grey must include this" , "Greyish brown" , "Grey-brown colour" .)