Artist's plaster (5)
I believe the answer is:
gesso
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">artist's plaster</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for gesso that I've seen before include "smeared on for starters by artists" , "Could get you plastered" , "Plaster of Paris" , "Type of plaster" , "Artist's plaster" .)