Complex sentence: This reduction was kept to a minimum by reducing the width of the normal KS perforations so that they were nearly square, but of DH height, thus, the CinemaScope, or CS perforation was born, known colloquially as "fox-holes".
Split into simpler sentences: This reduction was kept to a minimum by reducing the width of the normal KS perforations so that they were nearly square, but of DH height. This was the CinemaScope, or CS, perforation, known colloquially as "fox-holes".