Color Managing Images for Output

If your working color space does not match the color space of your deliverables, the colors must be transformed for output. When you are manually setting up a custom chain of transforms to accomplish this, there are several transforms that can be used, depending on your working space and the desired output.

If your images are scene-linear, you can convert them to ACES 2065-1 if necessary using one of the transforms in the primaries/ directory. After that:

• If you are targeting video or digital cinema, use one of the transforms in the RRT+ODT/ directory.
• If you are targeting a film recorder, use one of the ACES_to_ADX transforms in the film/ADX/ directory.

If your images are in a log space and you are not outputting to film, first apply one of the transforms in the film/ directory to convert them to scene-linear and then continue as above.

Managing Gamut for Digital Cinema

Digital Cinema Distribution Masters (DCDMs) require images in the DCI/SMPTE X'Y'Z' color space. The RRT+ODT/ACES_to_DCI transforms produce images in this color space (with variations for different creative white points).

However, this color space is much larger than that of any real projector. A typical cinema projector has a gamut closer to that of the DCI/SMPTE reference projector (P3 primaries).

Therefore, it is sometimes desirable to limit the gamut of colors placed in the X'Y'Z' color space to that of a more representative projector. This has two advantages:

• The gamut mapping is performed by the output transform (which preserves hue) rather than by the projector (which typically clips).
• Assuming that the content was graded and approved on a projector with a typical P3 gamut, limiting the colors to that gamut assures there will be no unpleasant surprises if the content is later viewed on a device with a wider gamut.

To achieve this:

1. Select the RRT+ODT for the device whose gamut you want to limit to, for example, RRT+ODT/ACES_to_P3-D60.
2. Then add transforms to convert to DCI/SMPTE X'Y'Z', for example, display/projector/P3-D60_to_CIE-XYZ followed by display/DCDM/CIE-XYZ_to_DCI-D60.