Band's jacket recommendation? Not black (4)
I believe the answer is:
blur
'band's jacket recommendation? not black' is the definition.
I can't tell whether this definition defines the answer.
'band's jacket recommendation? not black' is the wordplay.
'band's' becomes 'b' (this might be a standard abbreviation I've not previously seen).
'jacket recommendation?' becomes 'blurb' (a blurb is a recommendation on a book jacket).
'not' indicates named letters should be taken away.
'black' becomes 'bb'.
'blurb' with 'bb' removed is 'lur'.
'b'+'lur'='BLUR'
(Other definitions for blur that I've seen before include "Befog" , "Group - smudge" , "Become unclear" , "Fuzzy image" , "fade" .)