Difference in rendering after export in LrC

When you have images with extreme noise and are not looking at them at 1:1 scaling to the screen pixels, you can get very strong differences between apps depending on the scaling algorithm the app uses. This is a very common issue and is just caused by the math used to scale. Preview app uses a completely different algorithm from almost all other apps and indeed with very noisy images you will get vastly different appearance, even if everything is well calibrated. The develop display even uses a completely different scaliong algorithm again since it is done by subsampling the raw file and scaling in a lineart space and sharpening the image a bit. This is completely different to what happens in the library module and in extrenal apps which usually scale in a much narrower gamut and gamma corrected space. This will make noisy images appear more or less noisy and even shift average tone when viewed in different places. So make sure you look at the output jpeg at 1:1 zoom ratio if it is very noisy like the images in the screenshot. This is something you can't completely control since it depends on the scaling algorithm used by the viewer's viewing app. Only way to control it is to do the scaling to the screen resolution yourself but with the prevalence of mobile platforms and hiDPI/retina displays you also cannot really rely on that anymore.  Just be wary of very noisy images when displayed at different resolutions. 

In theory they should look the same…on my M1 Pro I was not able to create a difference. 

I’m pretty sure Preview is color-managed, so it’s odd that it’s looking different.

Similar to your Eizo ColorEdge, I am also using a wide gamut display that can be hardware calibrated.

I noticed that your image is monochrome, so I compared how a JPEG exported from Lightroom Classic looks in Preview using both a full color original camera raw file (exported as ProPhoto RGB to trip up any application that doesn’t read color profiles), and a grayscale mode TIFF file scanned from black and white film. But both looked the same in Preview, and the two screen shots (Lightroom Classic and Preview) of the grayscale image showed no difference when compared in Photoshop using the Difference blending mode. So I’m stumped.

These questions could help identify the problem…

What is the color model of the original that was imported into Lightroom Classic? (such as raw, RGB, gray, CMYK…) From the file names in your screen shot, I am guessing it was a camera raw file, so raw color?

How was the color removed from the original? Was it imported in color and then a Monochrome raw profile was applied in Lightroom Classic? Or was Saturation decreased in Lightroom Classic? Or was it taken to an application such as Photoshop, the color removed, and then imported into Lightroom Classic.

How was the grainy look added? Was it the Grain option in Lightroom Classic, or was it run through a filter in another application at some point before or after Lightroom Classic?

When it was exported from Lightroom Classic, what was the color profile selected in the Export dialog box, under File Settings, Color Space?

GPU acceleration freshly removed in LrC.

To be clear, this means that you have tried disabling the GPU in LrC, right?

an obvious difference in rendering between the image in LR's “development” module and its export seen in “Preview” mac application. When this export is viewed in an app that manages colors “correctly” (qView or nomacs), I have no problem.

I was under the impression that all Mac applications are color managed, including Preview.

Since this is not caused by the monitor profile, the only thing I can think of is a bug in the GPU driver that affects Preview, but not LrC.

If that's the case you have to wait for the driver to be updated through an OS update.

I'm a Windows user myself, maybe a Mac user, like @Conrad_C can help you.

Eizo Coloredge;
i1display.

 

Screen freshly factory reset, calibration freshly performed, LrC freshly uninstalled then reinstalled, GPU acceleration freshly removed in LrC.

 

By @L'hurluber.lu

LrC is very sensitive to the monitor profile. Try re-calibrating, and make sure to create a version 2 (not version 4), Gamma or Matrix (not LUT) profile. If you're using Color Navigator, see the screenshot below.

After calibration, any running applications must be relaunched to become aware of the new profile.

I have inserted your screenhsot below. In the future, please do not attach images, use the Insert Photos button in the toolbar to insert them directly in your posts.