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then convert the images to the P3 primaries by applying ACES_to_CIE-XYZ followed by
CIE-XYZ_to_P3-D60 from the primaries/ directory.
■ The rendered 3D CG elements are most likely scene-linear images already, but are probably using the
sRGB primaries (which are the same as the Rec. 709 primaries). You can convert these images to your
working space by applying Rec-709-sRGB_to_CIE-XYZ followed by CIE-XYZ_to_P3-D60 from the primaries/
directory (see
Color Managing Rendered 3D CG Images (page 1316)).
■ Suppose that the title cards are sRGB images. To convert them to scene-linear, you need to apply an
inverse tone map. One way to do this is to apply inversePhotoMap_gamma_2.4 from the tone-map/
directory (see
Color Managing Video Footage (page 1315)), and then convert the primaries in the same way
as for the 3D elements using Rec-709-sRGB_to_CIE-XYZ followed by CIE-XYZ_to_P3-D60 from the
primaries/ directory. However because you will be using the ACES RRT tone map for output (more about
that coming up), use the sRGB_to_ACES transform followed by ACES_to_CIE-XYZ and CIE-XYZ_to_P3-D60
— this ensures that the original sRGB values are unchanged by the matching combination of inverse
tone map for input and tone map for both display and output.
Set Up the View Transform
Now you need to set up your view transform to display these images as you work. Since the working space
is scene-referred, you need to use a tone map to convert the images to output-referred values, and of course
you should use the same tone map as the final deliverables. For the purpose of this example, suppose that
you decide to use the ACES RRT.
To use any of the transforms in the RRT+ODT/ directory, you must first convert to ACES. You can do this
using P3-D60_to_CIE-XYZ followed by CIE-XYZ_to_ACES from the primaries/ directory. Finally, you can
apply ACES_to_current-monitor from the RRT+ODT/ directory. Chromatic adaptation is built into these
transforms to map the D60 white point of the working space to the monitor's white point. Export this chain
of transforms as a single .ctf file and set it as your viewing transform.
In addition, you may want to preview on a projector calibrated to the DCI white point. You can first convert
to ACES using P3-D60_to_CIE-XYZ followed by CIE-XYZ_to_ACES from the primaries/ directory as above,
and then use ACES_to_P3-DCI from the RRT+ODT/ directory. Although the calibration white is DCI, the
creative white is D60, so chromatic adaptation is neither necessary nor built-in (see White Point Conversion
(page 1318)).
See
Color Managing Images for Display (page 1312) for more information.
Color Managing the Output
Finally, you need to apply the correct transforms for your deliverables. As for the display, you need to use
a tone map to convert from scene-referred to output-referred.
Once again, you can convert from the working space to ACES using P3-D60_to_CIE-XYZ followed by
CIE-XYZ_to_ACES from the primaries/ directory. After that:
■ For the DCDM, apply ACES_to_DCI-60 from the RRT+ODT/ directory.
■ For HD video, apply ACES_to_HD-video from the same directory.
See
Color Managing Images for Output (page 1313) for more information.
Color Transform Files
The color transforms included with Autodesk Color Management are supplied as individual files in CTF
format. In addition, Autodesk Color Management can import many third-party LUT and transform formats.
1322 | Chapter 25 Colour Management