P: Scaling issue in Photoshop but only when exporting from Lightroom Classic

"It's whatever they are on a clean install."

Unfortunately that doesn't help.  

I need to know the scaling on both Lightroom Classic: Preferences>Interface

I also need to know the scaling setings on the Windows OS for each monitor

These should all be percentage values. When you get that information, I should be able to make some recommendations. 

It's whatever they are on a clean install. Sorry I can't check at the moment but I've done a complete clean install of everything - photoshop and Lightroom, including deleting preferences in app data to ensure that everything was reset. The problem still persists. 

Can you confirm your scaling setting in Lightroom?

No - I think I said that above - if I Export from lightroom to the hard drive, using the same settings as Edit In Photoshop from Lightroom, it works perfectly. That is why it is so odd.

As a test, export the file from Lightroom to your hard drive using the settings in your Preferences>External Editor Preferences.

Open that photo from your hard drive in Photoshop. Does the file still misbehave?

Hi

No - I have tried that to see if that worked but no, I'm not, and if I put Photoshop onto the monitor that is 1920x1080 at 100% scaling then everything works fine, but it is my understanding that the scaling of the monitor shouldn't affect the image in this way.

I've just done (another) complete uninstall of everything photography related, including Photoshop and Lightroom, and I have also removed the relevant folders in appdata to make sure that nothing is lingering and everything is clean. I'm not hooked up to any other monitors and just using the laptop in its default state (15inch monitor, 1920x1080 and 125% scaling, which is all default settings).

As stated, it isn't a scaling issue in Photoshop as if I open a file manually in Photoshop it works (even if it is the same file that I just export to the desktop with exactly the same settings that Edit in Photoshop 2021 uses). But try and use Edit in Photoshop and the above occurs. I have tried different images etc but nothing seems to fix this issue. It is so frustrating.

Are you by chance sending a Cropped Virtual Copy from Lightroom to Photoshop?

No - nothing to do with the NAS - I copied some photographs onto my desktop and imported into lightroom, and still have the same issue

I have had a thought that maybe it could be down to storing the photographs on a NAS - I am going to try a test and see if that works

I have been using Lightroom on a 30" 2560x1600 monitor for the past 12 years. It was time to replace my monitor, so after doing some research, I got a 43" 4K monitor. (I have a desk deep enough to push the monitor back so it’s comfortable). The ppi on the 43” is about the same as the 30” at around 100ppi.

The Windows 10 display scaling is set to custom scaling at 115% and the Ease of Access Display settings are set at default. This gives me a good size of interface and crisp fonts on nearly all apps.

Photoshop scaling is fine. In Preferences, Interface, the UI Font size is set to medium with ‘Scale UI to Font’ disabled. I can fit a lot onscreen at a sensible size, with sharp fonts.

I’m having issues with Lightroom however. Whatever I do, the interface size is either too large or small. In the screenshots below you can see Preferences, Interface, Font Size set to Auto, Medium and Large – 150%.

The best size is Medium, but it is rather small and tricky to work with, as clicks on the Develop panel need to be very precise. As you can see from the comparison, the Large – 150% interface size is just too large. I can’t fit enough panels onscreen and loose too much space. I’ve also tried adjusting the program size in Properties, Compatibility, Change high DPI settings in the ‘High DPI scaling override’ sections, but that doesn’t make any difference.

Would it be possible for Adobe to give us more front size options? At the very least, one extra option which would be Large - 125%, which is a standard Windows Display option. That would allow the interface to adjusted more precisely and give better results, regardless of monitor size.