>>3543441>And what exactly does "antihalation" do?Picrelated, from the horse's mouth.
Actually the whole PDF is a nice, simple explanation of how colour negative film works.
>https://www.kodak.com/uploadedfiles/motion/US_plugins_acrobat_en_motion_newsletters_filmEss_04_How-film-makes-image.pdfWhen you don't have any sort of antihalation, you get halos around bright objects, like light sources.