Graeme Nattress
RED Problem Solver
3D LUTS don't seem to work under Legacy. Trying to enable John Schick's RED to Alexa LUT under Legacy as enabling it under IPP2 causes a double rendering of the transform to REC709. However, while 3DLUTs work in IPP2, it doesn't work in Legacy Image Pipeline.
Such LUTs combine a creative aspect and output transform. They can't be used in a system which also incorporates an output transform or else you get a double output transform.
In IPP2 by specifying creative LUTs to be output-transform-less it means users get greater flexibility - they're not tied to a single colour space or linearity but can use the creative LUT over HDR or SDR or Rec2020 or Rec709 or whatever. I've tested this process extensively here and a well designed creative LUT can work beautifully on a normal HDTV image, and then by the flip of the output transform switch pipe out to an HDR display with a different colour space and still perform and not unduly limit brightness or colour gamut either. It's a very flexible and powerful system.
Graeme