Is your screen calibrated?
Did you try to set the screen profile in Windwos to sRGB - just for testing purpose?
OT: Is this in the Alteschgletscher region?
The screen is calibrated
I have a second screen which uses the sRGB profile and the problem doesn't show off on that screen...mmmh
Seems to be a profile mismatch between Library and Develop modules. The file is in TIFF format with ProPhoto RGB profile. The camera profile in the develop module is set to "embed". If I open the file in Photoshop, it looks like the version in the lightroom library.
If I make a proof in Photoshop with an AdobeRGB 98 profile with "Preserve RGB number" checked, I get nearly the same value that I have in the Develop module. If I check the darkest value in the develop module I get a luminance value of 3 / RGB about 5% and in Photoshop, I still have a luminance value of 3, but the RGB value climbs to 10% (looking at that values, I'm too dark - I like to keep my deepest darks at L10).
OT: No, it is a bit more north-east. It is the Rhône Gletscher...
If I proof with Monitor RGB in Photoshop, I get the same BW values than in the Develop module of Lightroom!
I do not know now which values are correct... ,-(
When Library and Develop display differently, it is always due to a broken monitor profile.
As a test, set the monitor profile to sRGB in your computer's OS.
If this fixes the issue, calibrate your monitor with a hardware calibrator. (which is something you should do anyway)
Thanks for the tip...as expected (I already checked on an sRGB screen before), that solves the problem (even if there is still a very very very slight differences in the zone IV gray).
I will recalibrate my monitor to see if that solves the problem...
Found the culprit... Me!
I did a calibration again and everything works fine now... Thx Per, Thx McLion.
1. I calibrated a couple of week with a Gamma of 2.2. Adobe CC suite was synchronized with a Gamma of 2.2
2. Last week, I read somewhere that it is more efficient when working with luminance layers to use a Gamma of 1.8. I synchronized the CC suite with that value... without calibrating the monitor again
3. I noticed the issue last week-end
As soon as I recalibrated the monitor, the problem was solved... even if there is this slight, very, very slight difference in zone IV between Library and Develop module in Lightroom as well as in Photoshop (slighly darker)...