False color ocio?

The Filmic ocio by @Troy_James_Sobotka has a false color view transform which seemed pretty useful. What would be needed to use this in ACES?

I believe Filmic is in sRGB/Rec709 linear working space, and the false color LMT uses FilmicLogEncoding as it processing space. What would be the correct way to use that LUT in an ACES config?

One thing I figured I should do is change the matrix which gives the luma, and switch it use luminance weights for ACEScg based on this post

  - !<Look>
    name: False_Colour
    process_space: Filmic Log Encoding
    transform: !<GroupTransform>
        - !<MatrixTransform> {matrix: [0.272229, 0.674082, 0.0536895, 0, 0.272229, 0.674082, 0.0536895, 0, 0.272229, 0.674082, 0.0536895, 0, 0, 0, 0, 1]}
        - !<FileTransform> {src: Filmic_False_Colour.spi3d, interpolation: best}

The part I’m less sure about is the LMT process space:

  - !<ColorSpace>
    name: Filmic Log Encoding
    bitdepth: 32f
    description: |
      Log based filmic shaper with 16.5 stops of latitude, and 25 stops of dynamic range.
    isdata: false
    allocation: lg2
    allocationvars: [-12.473931188, 12.526068812]
    from_reference: !<GroupTransform>
          - !<AllocationTransform> {allocation: lg2, vars: [-12.473931188, 12.526068812]}
          - !<FileTransform> {src: desat65cube.spi3d, interpolation: best}
          - !<AllocationTransform> {allocation: uniform, vars: [0, 0.66]}
    to_reference: !<AllocationTransform> {allocation: lg2, vars: [-12.473931188, 4.026068812], direction: inverse}
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As it happens, I have just recently been experimenting with a false colour gizmo, with customisable colours and ranges (in stops). The current version uses the ordinary Nuke Colorspace node, which doesn’t include ACEScg. But I was thinking about changing the way it works so it just has a dropdown of common encoding combinations. I am happy to share it when it is done, if that would be useful to you.

That’s serendipity. Yes please!