Inland Empire was shot in SD 4x3 480i29.97 on DV tape. After being captured, the footage was edited in the same format in Avid. The footage was then converted to HD 16x9 1080p23.98 and input into Clipster for remote DaVinci 2K grading. During this process, a Teranex converter was used to treat video noise on selected shots. With the digital-intermediate (DI) master complete, it was output to 35 mm film and HDCAM-SR tape. In 2021, the HDCAM-SR source was recaptured and upscaled to UHD/4K 16x9 via numerous algorithms in Topaz Labs’ Gigapixel AI software. Those tests were compared against the original HD video master as well as a 4K scan of the first reel of the 35 mm digital negative. From these tests, director David Lynch chose the upscale made using the GaiaHD algorithm and footage that had first been downscaled back to SD in order to throw away false detail introduced during the original HD conversion and allow the most effective use of the AI upscale (footage upscaled directly from the HD was less noticeably “4K-looking”). After the entire movie had been processed, it underwent quality control for image-breaking artifacts, such as faces becoming garbled. Several shots were flagged and then redone using the next best Gigapixel setting. Once the upscale was complete, the 4K image was brought into DaVinci Resolve for a new color pass to manage color balance and saturation as well as add a slight layer of grain. The audio presented for this release was remastered in January 2022 by the film’s original rerecording mixers, Lynch, Ron Eng, and Dean Hurley. Working from the original 5.1 mix stems, careful scene-by- scene adjustments involving noise reduction, dialogue levels, and overall dynamics decisions were made under Lynch’s supervision. This new mix preserves the overall color and channel assignment of the original mix, which by design maintained a “front heavy” delivery of the mix’s energy, with intentionally minimal surround activity. The DCP was authored using the easyDCP plug-in for DaVinci Resolve.
— prefectart (Reddit comment)