Complex sentence: For a long time, filming could not begin because the State Committee for Cinematography (Goskino) would not accept the screenplay, considering it propaganda for the "aesthetics of dirtiness" and "naturalism".
Split into simpler sentences: For a long time, filming could not begin. The State Committee for Cinematography (Goskino) would not accept the screenplay, considering it a propaganda for the "aesthetics of dirtiness" and "naturalism".