In the latest edition of American Cinematographer, colorist Yvan Lucas says that the amazing saturation achieved in Tarantino's latest film "Once Upon a Time in Hollywood" comes: "partly from the print stock, 2383. Kodak came out with it about 20 years ago. This film print is very colorful, and the primary colors are really separated and very pronounced. It's almost astounding. You get true red, green, and blue - and Quentin told me 'When I see those colors, that's when I know it's film.'"
My question is, what exactly is meant by "separation" on a technical level? Is this not possible on digital? What qualities would this film stock have that simply shooting with 4:4:4 or 4:2:2 video wouldn't be able to achieve? I've also felt that color is what separated film from digital, but I can't seem to understand why.
Does anyone have any insight into this? Would be very much appreciated!