Complex sentence: The lettering in the comics of the sensationalist horror comics publisher EC Comics c.1945--c.1955 was different from other publishers--its mechanical appearance gave it a sterile aspect, and helped define the particular style of comics EC was known for.
Split into simpler sentences: The lettering in the comics of the controversial short-lived publisher EC Comics was different from other publishers. Its slightly mechanical look gave it a sterile aspect, and helped to define the particular style of sensationalist horror EC was known for.