Complex sentence: Seeman accomplished this by using a dark room with the light tightly controlled so that the only light fell precisely where Seeman wanted it, and he used a velour background (dark and absorbs stray light).
Split into simpler sentences: Seeman accomplished this by using a dark room with the light tightly controlled so that the only light fell precisely where Seeman wanted it. He used a velour background (dark and absorbs stray light).