Oh it’s not heated - apologies if I made it sound that way!
To complete this exchange.
The luminance noise is between levels 1 to 4 exceptionally 5
The chrominance noise is up to level 6, exceptionally 7 when there are large blotches
Only mildly heated but in a constructive way.
@charlyw64 had good reasons for his argument, and I hadn’t thought about that problem before this post. So it was informative.
Thanks @Morgan_Hardwood, inspired by, among others, some of your processings, I rediscovered the fabulous curves in the Lab Adjustments tool, like LH, CH, etc… I used those extensively on the set of images shot in that city (btw it is Graz in Austria).
Also thanks, for the nice pictured example you gave.
@jdc, thanks for the information!