How to view the clipping warning for gamut and luminance separately on darktable 3.4

I’ve reviewed the manual regarding the exciting new modes that the clipping warning utility module provides in darktable 3.4, however I am still unclear about how to use it to check for luminance clipping (which I would likely correct for using the exposure or filmic rgb modules) and gamut clipping (which I would likely correct for using the color balance module). I don’t believe the default full gamut mode distinguishes luminance verses gamut clipping (they both appear as the same colors) so right now I have been doing the following:

  • set clipping preview mode to luminance only
  • fix luminance clipping in exposure or filmic rgb
  • set clipping preview mode to saturation only
  • fix gamut clipping in color balance

Am I missing something about how to use full gamut to tell which modules to use to adjust the clipped areas? It would be great if there was a shortcut to toggle between the clipping preview modes.

Also, am I correct in understanding (from what the manual says) that for normal sRGB images I should set the lower threshold to -12.69 EV? If I then want to export an image for printing, even if I am sending it to the printer in Adobe RGB format (which clips at -19.79 EV), I should still set the clipping indicator to -8.00 EV for color glossy prints to check if it is clipped? Also, are lustre prints likely the same as glossy?

From what I have read on the forum, setting the upper threshold to 99.99% should be fine so that you don’t think you are clipping pixels which aren’t actually clipped (but just at the very top of the usable range)?

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Adding to Andrew’s questions, I’d like to know what lower threshold should be set to if we are outputting 16 bit linear rec 2020, and 16 bit linear pro photo rgb, for instance, if we want an uncompressed tiff to work on in another program. 8 bit of those two spaces would also be helpful to know.