For many years, all computer monitors had about the same pixel density. This meant that 72 pixels always represented about an inch of physical display, and the UI of all applications (including Photoshop) were designed with that in mind. High-density (HiDPI) displays started to become popular in 2012, and brought with them a new challenge: if a monitor is twice as dense (a scale factor of 200%, or 144 pixels per inch) then the UI of Photoshop will become twice as small. If it is even more dense, the problem only gets worse and the UI smaller. Today, it is difficult to find a laptop that isn’t HiDPI. On the desktop, we commonly see very high resolutions at 4k, 5k, and 8k. To solve this problem on macOS, we took advantage of Apple’s pixel doubling technology and were able to support a 200% scale factor on Retina displays back in 2012. Windows, however, has a much broader set of hardware options and pixel densities, and required a more complex (and more difficult) solution.
Today we are shipping support for Windows high density monitors in Photoshop 19.1. I hope it improves your experience with Photoshop on HiDPI monitors as much as it has mine.
For more information about the complete release and all the features it included, go here.
Principal Scientist, Photoshop