The Sorcerer’s Stone and The Chamber of Secrets received full 4K scans from their original 35mm film negatives. These films show the most dramatic improvement, with visible textures in costumes and clear background details in the Great Hall.
The most significant draw of the 4K collection is the visual overhaul. While the original Blu-rays were impressive for their time, the 4K UHD versions provide a "night and day" difference in several key areas:
Revisiting Hogwarts: Is the Harry Potter 4K Collection Worth the Upgrade? For many of us, the Harry Potter
Because 4K discs have large file sizes, studios usually put the movie on the 4K disc and put the special features (documentaries, deleted scenes, interviews) on a standard Blu-ray disc included in the case.
Harry Potter: 8-Film Collection [4K Ultra HD + Blu-ray] is a comprehensive set that offers a significant technical upgrade over previous standard Blu-ray releases.