Complex sentence: He specialized first in "ethnic films," notably four in Yiddish, and then found a niche making melodramas on miniscule budgets and with often unpromising scripts and actors for PRC (Producers Releasing Corporation).
Split into simpler sentences: He specialized first in "ethnic films," notably four in Yiddish. Ulmer then found a niche making melodramas on miniscule budgets and with often unpromising scripts and actors for PRC (Producers Releasing Corporation).