Lab assistant of film (4)
I believe the answer is:
igor
'lab assistant of film' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for igor that I've seen before include "Prince in Borodin's opera" , "Russian man" , "Hero of Borodin" , "Prince of Russian opera" , "Stravinsky's first name" .)