Artist's mixing board (7)
I believe the answer is:
palette
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">artist's mixing board</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for palette that I've seen before include "Armour" , "Painter's utensil" , "Artist's paint mixing board" , "Painter's board" , "Board on which painter mixes colours" .)