BFI

No clear winner, Criterion SDR 4K Blu-ray has better defined grain and is cleaned-up more thoroughly. But looks grayer and flatter in daytime scenes. BFI 4K Blu-ray's HDR/DV is better in contrast but the grading can be debatable.

The subtitles of Criterion  and BFI are translated differently. See BR forum.

> Criterion > StudioCanal

BFI 4K Blu-ray has excellent master and grade, no DNR and tasteful HDR

The unrestored track on BFI's earlier release appears to be an almost entirely unmanipulated transfer of the original mix. It suffers from a distracting low-frequency hum. The 4K restoration comes with a restored track, which appears to be the same transfer, but which appears to be cleaned up with a moderate amount of noise reduction and some EQ, nicely opening up the high-end, and which is likely to be preferable to most listeners. All earlier releases sound poor.

Perspecta isn't a discrete surround format, instead only relying on manipulating volume and panning of the mono track across L/C/R channels, based on embedded control tones. As such, even the Perspecta track is technically just the mono mix, though the omission of the proper mono on BFI's 4K is still unfortunate.