Complex sentence: Their experiments, which continued after they finished college, turned from multiple lenses that produce multiple, differently coloured images that had to be combined to form the final transparency, to multiple layered film in which the different colour images were already combined, perfectly aligned.
Split into simpler sentences: Their experiments, which continued after they finished college, turned from multiple lenses that produce multiple, differently coloured images that had to be combined to form the final transparency, to multiple layered film. Film in which the different colour images were already combined, perfectly aligned.