I engaged with a tech and he was not able to help me. We tried a few things. Then he said that the library view and devlop view are expected to be different. He did not say why.
This thread indicates that noise reduction and sharpening are not applied in the library. Is that so? If so, why? Kind of weird.
I may very well delete an image in the library based on the preview there. Some of these in my crrent project are very different. The exports look right as far as I can tell.
Anybody else notice this or have a solution, if there is one? ;-)
As far as what could be contributing to a difference, other than an actual bug:
LR Previews are stored as AdobeRGB JPGs, so Library previews go from LR-Internal color profile to AdobeRGB to Display color profile, whereas Develop previews go directly from LR-Internal color profile to Display color profile. If there are some colors that are outside of AdobeRGB then some conversion may occur. The conversion to 8-bit JPG is also probably adding banding that Develop wouldn’t show. There might also be Relative vs Perceptual color profile conversion differences occurring. I don’t know the specifics of which is used for the Adobe color profile conversion and whether what you’re seeing is outside the expected variations.
If you view at less than 1:1/100% zoom, especially with Fit or Fill, then small details that vary across the group of original image pixels that are displayed as one display pixel can be averaged differently due to differences in the downsampling algorithms used between computing Library file previews and computing Develop display previews where Develop’s is built for speed because it occurs in real-time after every slider movement, where Library previews are computed in the background and so can use a more accurate resampling algorithm. Usually this is only a difference in sharp/smoothness but it can also manifest as a difference in tone if there are lots of tiny noise spots getting averaged together inaccurately in Develop or more accurately in Library.
Since I can see only a tiny difference between Library and Develop on my monitor in this particular example, I can't imagine that small difference is enough to reject the Library version and accept the Develop version. Maybe you're seeing others with more differences?
Thanks for the reply. You're probably right about there not being enough of a difference to reject. I guess I was afraid there may be worse cases in the future. The sky is a smoother gradient in Develop and overall much more pleasing. In the Library it looked like I had not made the edits that I had, or at least not all of the changes were visible. I looked at some other images from other folders and see a subtle difference there too.
Subtle changes are to be expected for at least the reasons, above.
Obvious changes not replicating would be a problem, usually a corrupted preview cache.