Complex sentence: The ILM team reportedly searched through countless hours of footage to find suitable material of Cushing to build from, footage from "A New Hope" was lit very differently to the lighting used in "Rogue One" and had to be digitally changed.
Split into simpler sentences: The ILM team reportedly searched through countless hours of footage to find suitable material of Cushing to build from. Footage of Cushing from "A New Hope" was lit very differently to the lighting used in "Rogue One" and had to be digitally changed.