Increasingly, I find myself wishing to preview a Luminance histogram when making edits in the RGB color space and would find it useful if the Luminance histogram were added to the choices for the Histogram Tool...
For now, a work around is to Extract an image's Luminance channel and open the Histogram Tool in HSV-V mode on it... ...but Extract Channel is often unavailable without first closing an 'active' editing transform... ...and potentially needing to subsequently re-open it...
...Thank you for the consideration... ...den...
Histogram Tool and Luminance
Moderator: jsachs