Not glossy, as a photo finish (5)
I believe the answer is:
matte
(Other definitions for matte that I've seen before include "Mask used to add an image in front of camera" , "Mask used to block out areas of the image in filming" , "Mask used to record two images on same film" , "Mask used in film; ET mat (anag.)" , "Dull, flat" .)