Color Managing Images from Scanned Film

Images from scanned film are typically supplied as DPX files with Cineon-style log encodings. However, the Cineon encoding was never fully standardized, and various vendors use slightly different implementations.

Academy Density Exchange (ADX) is a standard developed by AMPAS to eliminate any confusion and standardize on a single implementation. ADX is part of the ACES system, and is included in the SMPTE 2065 set of documents.

There are a couple of transforms for importing ADX-encoded images as scene-linear values. If you are importing DPX files from a properly calibrated ADX scanner, use one of these transforms:

If the images did not come from an ADX scanner, try importing them with one of the ADX transforms anyway as a first resort. If you are not satisfied with the result, you can try one of the Log_to_Lin transforms in the film/LogLin/ directory. However, be aware that these transforms modify each color channel independently (similar to 1D LUTs), and do not attempt to account for the channel cross-talk in film like the ADX_to_ACES transforms do.

Alternatively, you can try using one of the print-film emulation LUTs in the Lustre Color collection, if they are available to you. These transforms are installed with the Autodesk Creative Finishing products, as well as with Autodesk Composite. The transforms are supplied in the legacy .3dl format, and can be imported by Autodesk Color Management. Refer to the Lustre Color Management User Guide for more information about the transforms in that collection.

Note: DPX files may contain values other than Cineon-style log-encoded colors. For example, they may contain video colors. When working with DPX files in general, you need to know the specific color encoding used. There may be metadata available in the files, but even when metadata is present it can be incorrect or misleading.