Sharpness test
Text that looks soft on a monitor is almost never the monitor. It is the signal arriving with the colour detail thrown away, the picture being resized on its way to the panel, or the operating system smoothing letters for a subpixel layout the screen does not have. Each of those ruins a different pattern, so four patterns tell them apart — and each has a fix that costs nothing.
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Were the fine patterns clean and the text sharp?
The four patterns
Colour detail. Two columns, the same geometry in both: fine lines and a one-pixel checkerboard, in black and white on the left and in red and blue on the right. Brightness detail survives chroma subsampling; colour detail does not. If the left column is crisp and the right is a flat purple smear, the signal is arriving at 4:2:0.
Pixel grid. A one-pixel checkerboard across the whole screen, with bands of one-, two- and three-pixel lines below it. At native resolution with integer scaling the checkerboard reads as flat grey, because every pattern pixel lands on one panel pixel. Anything else — a stretched picture, a fractional scale, browser zoom — breaks it into ripples.
Subpixel order. Widely spaced one-pixel white lines on black. Each line is exactly one pixel, which means exactly one red, one green and one blue stripe lit side by side, and the edges fringe with the outer two colours. Red on the left and blue on the right is RGB; the reverse is BGR. A phone camera zoomed in makes it obvious.
Text. Real text at nine to twenty pixels, in a sans and a monospace, black on white. This is the one pattern the browser renders rather than draws, so it shows the operating system’s smoothing as it is, on whatever it has decided the panel is.
Which fix
Colour smeared: the link. Try DisplayPort if the display has it. On HDMI, a certified high-speed cable and the newest port on both ends. On a television, find the per-input setting that enables full colour — Samsung calls it Input Signal Plus, LG calls it Ultra HD Deep Colour, Sony calls it Enhanced format — and set the input’s icon to PC where the menu offers it, which also switches off the processing that adds delay. In the graphics driver, check the output colour format is RGB or YCbCr 4:4:4.
Ripples: the resolution or the scale. Set the display to its native resolution — the one the monitor’s own specification names, which is also the one the resolution readout reports as the physical size. Then set scaling to 100% or 200%. If 100% is too small to read and 200% is too large, a fractional scale is the compromise, and the softness is its price.
Fringes reversed: the panel is BGR. On Windows, run the ClearType Text Tuner from the Start menu; the first screens let it work out the order by asking which sample looks best, and it stores the answer. On macOS the question does not arise — it dropped subpixel smoothing in 2018 and renders greyscale on everything.
Text soft, patterns clean: the smoothing itself. Windows: the ClearType tuner again, run to the end. macOS: font smoothing can be strengthened or disabled from the terminal, and on a low-density external monitor disabling it is often sharper. Linux: the hinting and antialiasing settings in the desktop’s font panel, and the subpixel order beside them.
Windows 11
- Settings → System → Display → Scale is where fractional scaling lives. 125% is the default on many 1440p monitors and is the single most common cause of soft text on a healthy panel.
- Display resolution, on the same page, should match the panel — Windows marks the native one as Recommended.
- ClearType Text Tuner is a separate application; type ClearType into the Start menu. Run it on every monitor separately, because it stores an answer per display.
- In the NVIDIA Control Panel or AMD Software, the output colour format for the display should read RGB or YCbCr444. If the only options are 4:2:0 and 4:2:2, the link is bandwidth-limited.
macOS
- System Settings → Displays offers a row of scaled resolutions. The one marked Default for the display is native; anything to its left is rendered larger then downscaled, and on a non-Retina external monitor that softens text noticeably.
- macOS has no subpixel smoothing and no ClearType equivalent. On a low-density external monitor, text is greyscale-smoothed and there is a limit to how sharp it can look.
- A 4K television over HDMI often reports itself as a TV, and macOS may then send YCbCr 4:2:0. Forcing RGB needs an EDID override, which is beyond a settings change — DisplayPort or a USB-C connection avoids the question.
When it is the panel after all
If every pattern is clean and text is still coarse, the panel’s pixel density is what you are looking at, and it is not a fault. It is worth knowing the number before buying the next screen: pixels per inch is resolution divided by size, and text stops looking coarse to most people somewhere above about 110.
Common questions
What is chroma subsampling and why does it blur text?
A way of saving bandwidth by sending colour at lower resolution than brightness. Your eye is far more sensitive to brightness detail than to colour detail, and for video it works — nobody notices in a film. Text is different: a red letter on a blue background is nothing but colour detail, and at 4:2:0 the edge between them is averaged with its neighbours and turns to mush. The colour-detail pattern here puts fine black-and-white lines beside fine red-and-blue ones; brightness survives, colour does not, and the difference is the diagnosis.
Why would my connection be using 4:2:0?
Because it ran out of bandwidth and dropped colour rather than frames. HDMI 2.0 cannot carry 4K at 60 Hz with full colour, so a 4K display on an older HDMI port or a poor cable will silently fall to 4:2:0. Televisions used as monitors do it by default and need a mode — often called PC, Game, UHD Colour or Enhanced — switched on per input. Graphics drivers can also be set to it. DisplayPort almost never does this, which is why it is the first thing to try.
The pixel grid shows ripples. What does that mean?
That one pixel in the pattern is not landing on one pixel of the panel. Either the display is running below its native resolution and the monitor is stretching the picture, or the operating system is scaling by a fraction — 125% or 150% — and drawing a one-pixel line as one and a quarter pixels. Both soften everything. Native resolution and a scaling of 100% or 200% remove it; anything else is a trade of sharpness for size.
What is RGB versus BGR, and why does it matter?
Each pixel is three stripes, red, green and blue, and most panels order them left to right in that order. Some — several popular 4K and QD-OLED models — order them the other way. Text smoothing on Windows exploits the stripes to sharpen letter edges, and if it assumes RGB on a BGR panel every edge gets a colour fringe on the wrong side and looks worse than no smoothing at all. The subpixel pattern shows the order directly; the fix is a single step in the ClearType tuner.
Does this apply to a laptop screen?
The scaling and subpixel parts do; the chroma part almost never, because a laptop panel is connected internally at full bandwidth. A laptop with soft text is usually at a fractional scale — 150% is the default on many 14-inch machines — and the honest answer is that it is the price of a screen that size, not a fault.
Why does the test ask me to reset the browser zoom?
Because zoom scales the page, and a pattern that has been scaled has already lost the one-to-one relationship with the panel that the test depends on. At 110% zoom the pixel grid would ripple on a perfectly healthy screen. Ctrl+0 or Cmd+0 puts it back.
Everything is clean but text still looks worse than on my old monitor.
Then the difference is pixel density. A 24-inch 1080p screen has about 92 pixels per inch, a 27-inch 1080p about 82, a 27-inch 1440p about 109, a 27-inch 4K about 163. Fewer pixels per inch is coarser text and no setting changes that. If you moved from a smaller screen to a larger one at the same resolution, this is what you are seeing.