In a nutshell, IIF-ACES is a workflow that eliminates ambiguities that currently exist in the digital pipeline regarding transforms, color space and file formats. IIF (Image Interchange Framework) is an architecture for advanced motion-picture imaging, and ACES (Academy Color Encoding Specification) encodes the images from the source."When things are ingested into a Rec. 709 workflow, you’re constrained by the color gamut of Rec. 709, as well as by the dynamic range," explains cinematographer Curtis Clark, ASC. "With the ACES workflow, it enables the full dynamic range and full color space to be faithfully maintained within the post finishing process."
The ACES workflow was the genesis of the Academy of Motion Picture Arts and Sciences back in 2008, and it since has been embraced by the ASC Technology Committee, which is headed by Clark. The first production to use the ACES workflow is FX Networks’ hit show Justified, starring Timothy Olyphant as U.S. Marshal Raylan Givens and shot by cinematographer Francis Kenny, ASC, with Sony SRW-9000PL cameras. Kenny shot the first season of Justified with the Sony F35, but switched to the 9000PL due to its lighter weight. In the first season, Kenny was shooting in Sony’s S-Log, S-Gamut format, but started seeing discrepancies between what he was seeing in his RAW image compared to the end result that was coming out of his coloring sessions at Encore Hollywood. To their credit, Encore was very open to using the ACES workflow.
"Basically, what happened with Justified was that we were working like everybody had been used to working in television, which is taking the original capture, applying some sort of Log to Linear LUT and then working with the video tools of Lift, Gamma, Gain and working in the Rec. 709 color space," explains Encore Hollywood and Justified colorist Pankaj Bajpai, who uses Autodesk Lustre to grade the show. "When Francis, who has an extensive film background, started talking with Curtis about the S-Log, S-Gamut format of the Sony cameras—the F35 and the 9000PL—they raised the question if there was a solution out there that can create more filmic images. Up until that point, IIF-ACES was only being discussed for theatrical release, which uses P3 color space."
Along with the Academy and Clark’s ASC Technology Committee, Bajpai explains that Doug Walker, head color scientist for Autodesk, became an integral part of Encore’s adoption of ACES, as well as Sony, Fujifilm, Baselight and Colorworks.
"When I started to explore what IIF-ACES was doing, I immediately saw that you could get out of the bottleneck of the Rec. 709 limitations," says Bajpai. "A significant improvement in dynamic range, you actually see the range that people only talk about because the camera manufacturers are saying S-Log, S-Gamut can record X number of stops."