I exported a Photoshop formatted CUBE LUT and expected it to match (reasonably) when used in Camera Raw (in Photoshop). It does, generally, but shadows (and possibly highlights) are clipping and showing in red. If applied via Color Lookup adjustment layer in Photoshop, though, it's okay.
Further, when I upload the LUT to the Color.io LUT preview tool, the entire image has a red cast, and the visualization of the LUT appears to have some issues. This is also true when I export a generic CUBE LUT (shown in the screenshot attached).
Export a 64^3 LUT targeting Photoshop with Adobe RGB. Here's the settings/preset url, for reference.
Edit: It looks like this is related to the Adobe RGB color space conversion. If I choose "Same as preview" when exporting the LUT everything looks correct and it works in Camera Raw correctly, albeit with a slight shift in lightness/saturation (maybe gamma? I'm no expert here).
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Hi @corey - those red artifacts are definitely due to negative values (which the LUT previewer also doesn't handle). But I'm not sure the "Adobe RGB" setting in the export menu is doing quite what you'd expect it to do in Adobe Camera Raw... Essentially the "Adobe RGB" LUT requires the input signal to the LUT (ie your source image) to be encoded as Adobe RGB. Similarly your output device must be setup to display Adobe RGB unless there's a conversion from Adobe RGB to your target color space in the processing pipeline somewhere after the LUT. Using "Same as preview" is almost always the right and most compatible way to go without opening up a huge can of worms.
For color managed, wide gamut photography workflows my suggestion would be to set the IDT and ODT to "Color Space Conversion -> P3 D50/D60" and leave the export color space as "Same as preview". P3 nicely maps to and from ACES which Color.io uses internally whereas many other large gamut color spaces don't round trip as nicely and require additional gamut compression steps in the target software due to negative values, superbrights etc. Similarly, for color managed video workflows I would almost always suggest to export ACEScct LUTs as almost all other options introduce a ton of complexity.