Full HD on 4K monitors and most 4K TVs looks worse than on Full-HD monitors and TVs.
This happens due to blur added by all monitors and absolute majority of TVs at any scale, though this could be avoided when enlarging by an integer number of times (e. g. 2 in case of FHD→4K).
As a result, sharpness in videos and 3D games is decreased, white lines are gray, and pixel art is not pixel art anymore.
Each logical pixel could be displayed as a square group of integer (2×2, 3×3) number of physical pixels of the same color without mixing-in colors of adjacent pixels.
If the native display resolution and logical resolution are not divisible, we can use the maximum integer scale that the scaled image fits the screen at, and fill the rest space with black, like in centered mode without scaling.
Such lossless scaling is already built into graphics drivers and some software video players and removes blur regardless of monitor or TV used. But such prescaling is impossible if the signal source is not a computer, but e. g. a game console or a hardware video player.
Also, prescaling wastes bandwidth of video interface (HDMI, DP). This may sacrifice refresh rate and color depth.
- Complain of blur to technical support of your monitor/TV manufacturer.
- Ask about support for nonblurry scaling in comments to reviews of monitors and TVs in mass media.
- Request the feature for game engines that don’t have it.
- Tell about the issue to as many people as possible.
- AMD: supported for GPUs based on the 2nd-generation GCN () and newer architectures in Radeon Software 2020 (19.12.2+) () for Windows 7/10; being implemented for Linux.
- Intel: supported for Gen11 GPUs in the driver 18.104.22.16855+ () for Windows 10; available since in laptops equipped with Gen10 CPUs based on the Ice Lake architecture.
- nVidia: supported with limitations for RTX and GTX 16* in the driver 436.02+ () for Windows 10; incompatible with HDR, tiled mode, custom resolutions, 4:2:0, sharpening, DSR, and hybrid-GPU laptops.
- Linux: supported in Proton 4.11-10+ () (used in Steam Play); limited support in XRandR 1.5.1+ () and nVidia graphics driver 384.47+ (): image is cropped in many games.
- Monitors: supported in 27″ 4K and QHD monitors
Dough Spectrum based on LG Nano IPS panels with refresh rates up to 144 Hz (QHD, 4K) and 240 Hz (QHD); 4K model is already being shipped to customers, QHD@240 and QHD@144 are expected in and correspondingly.
- Standalone scalers: RetroTink-4K ($1000) and Morph 4K ($400-500) are expected to release in late 2023, with support for 4K output, integer scaling of digital and analog signals, and simulation of CRT displays.