Using the ACEScc and ACEScct Colour Spaces

ACEScc and ACEScct are working colour spaces that is recommended for colour grading when using the Academy Color Encoding System. ACEScc has a purely logarithmic encoding curve which allows very precise control over deep shadows but which can also be difficult to work with when not using the Log style grading tools. ACEScct is a more recent working space that compresses shadows similar to familiar camera log curves and which may be easier to grade. If you need to apply an ASC CDL from an on-set ACESproxy workflow, then you should use ACEScc as the working space. The following instructions are explained using ACEScc, but the steps are essentially the same for ACEScct.

1. In the Calibration settings of the Project Configuration settings, make sure that float_identity.fclut is selected as the Float Conversion LUT.
2. Import your OpenEXR media. You must do this using the Wiretap Gateway.
   Note: If you are accessing media that was imported to a Smoke or Flame system with the Cache Source Media option enabled, that media is no longer considered Gateway media. It is seen by Lustre as managed media and hence the LUT and Resize on import options are not available. To work around this, you can perform a Flush Cache Media operation in Smoke or Flame, prior to importing in Lustre.
3. Assuming that the clips are in the ACES2065-1 colour space, open the Image / Transcode / LUT Options menu, make sure that Colour Transform is selected under Conversion LUT Type, and look for ACES2065-1_to_ACEScc in the Conversion LUT list.
   If ACES2065-1_to_ACEScc is not already available, you'll need to add it. To do this:

   1. Click the Browse button (...).
   2. Click the Bookmark field and select the Autodesk location.
   3. Import interchange/ACESproxy/ACES2065-1_to_ACEScc.ctf.

   If the clips are not already in ACES2065-1 space, then you may go into Custom mode and first apply the Input Transform (IDT) to convert to ACES2065-1 before applying the working space transform.

4. For each clip, select ACES2065-1_to_ACEScc in the Conversion LUT list and click Enable.
5. If you are using CDLs, make sure that Post Input LUT is selected on the Image / CDL menu.
6. On the Render / Output menu, select a custom transform that converts back to the ACES2065-1 colour space and then applies the ACES reference rendering transform (RRT) and output device transform (ODT) for your deliverables, and click Enable.
   If you have not already defined an appropriate custom transform, you can do so as follows:

   1. Make sure that Colour Transform is selected under Conversion LUT Type.
   2. Click Custom.
   3. Click Add.
   4. Click Type and select Autodesk/interchange.
   5. Click Transform and select ACESproxy/ACEScc_to_ACES2065-1.ctf.
   6. Click Add again.
   7. Click Type and select Autodesk/RRT+ODT.
   8. Click Transform and select the appropriate transform for your output deliverable, such as ACES_to_P3-D60_1.0.ctf.

Note: Currently both these transforms must be applied together. You may not move just the RRT+ODT part to Setup/Calibrate for an ACEScc workflow. This means that if you want to render out ACES2065-1 files, you will need to delete or mute (shift-M) the RRT+ODT transform before rendering.