Problems With Using a 4K Monitor with 200% UI Scaling

Raiphoto  wrote I'm having problems with viewing images at 100% with Photoshop's UI scaling at 200% using a 4k monitor. When viewing images at 100%, especially with low-res images, the quality is noticeably worse than when viewing images at 100% with UI scaling at 100%.

There should be no diffence in image quality with uI scalling 100% or 200% set.  The image is scale the same way by photoshop not mater what the UI setting is set. Photoshop Scale UI elements 2x when 200% is set. Your brains is playing tricks one you.  The image display should be the same with either setting.

The position on screen will be different and there may be less of the image displayed on the screen because of the scalling of the UI elements there is less display area to display the image in.  Zommed to 100% you image pixels are being displayed with your displays native pixels there is no scalling. You viewing your image's pixels with your Displays DPI resolution.  The Image's resolution dpi setting means nothing it not used for anything on displays. Displays can not change their pixel size.

You image is not displayed print size and print sharp the pixels used to display the image are the wrong size the not the size pixels they woul be used pring the image. If you have a 4K 13: laptop the image display may actually be smalers and sharper than print size.   It the actual DPI resolution that is being use that renders the image size and sharpness.

If you overlay them, you'll see that there is a tiny bit of horizontal - but not vertical! - scaling to the 200% UI version. It's just enough to soften the result considerably, by sub-pixel interpolation of all sharp transitions.

This looks like a bug, unless there is something else that could have caused this tiny stretching. See if you get some response at the feedback forum.

https://feedback.photoshop.com/photoshop_family/categories/photoshop_family_photoshop