If Adobe documents the format of RGB LUTs stored in enhanced profiles, then it will be straightforward for LR plugins to make it much easier for users to import video LUTs as enhanced profiles and apply them to their images.
There are hundreds, perhaps thousands, of existing LUTs, primarily used for video editing, and most of those are in Rec 709. There are several roadblocks to users wanting to use those LUTs in LR:
- Camera Raw doesn't allow the Rec 709 gamma 2.2 and 2.4 color spaces when importing a LUT into a new enhanced profile:
https://feedback.photoshop.com/photoshop_family/topics/camera-raw-add-rec-709-to-lut-color-spaces-in...
- A user would need to buy an expensive utility to convert Rec 709 LUTs to a supported color space (e.g. ProPhoto RGB or Rec 2020).
- While LR 7 users will have access to Camera Raw via Photoshop (included in their CC subscription), many of them are unfamiliar with Camera Raw and would find the steps for creating enhanced profiles obscure and daunting.
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My current surmise for how the LUTs are encoded:
- The LUT is converted to the internal LR/ACR working space (ProPhoto RGB primaries and white point, linear transfer function).
- It is compressed somehow.
- The compressed LUT is then encoded using a minor variant of Ascii85.