Thank you for the responses.
And your explanation of the influence of one colour over the other is very good, Peter.
Actually my environment when soft proofing is dark and I expand the LR window to a maximum to minimize such effects.
Of course, there are always some thingies around
But looking at the samples I used as an example, they ARE different.
The point is making them match. If the proof were warmer, I'd try to cool it down and viceversa.
In theory I'd expect both parts, the original (50% gray) and the proof, to look exactly the same
In the samples the left side RGB is (128,128,128) and the right side (127,126,132).
A match would bring the right side to (128,128,128).
As a starting point, of course
Another thing I noticed is that changing the temperature values (WB) on the white card changes nothing. Even the Histogram stays put.
Would that mean that these sliders have more influence on some (exposure) values than on others?
Please don't forget that I am a newbie in digital matters. Excuse me if I state the obvious