Sharpness test
Device-pixel line patterns, small coloured text and a subpixel check. Together they show whether your display is showing every pixel crisply, at the right scale, without halos or colour smearing.
1-pixel patterns
Each block should look like an even, flat grey from a distance, and like crisp lines up close. Moiré, uneven stripes or a blurred block point to scaling below native resolution, or to overscan on a TV (turn on "Just Scan" / "Screen fit").
Text clarity and chroma subsampling
Sharp white on black, 12 px: the quick brown fox jumps over the lazy dog 0123456789
Sharp black on white, 12 px: the quick brown fox jumps over the lazy dog 0123456789
Blue on red: smeared or unreadable = chroma subsampling (4:2:2/4:2:0)
Yellow on blue: should be as crisp as the white text above
Halos around these letters on grey mean monitor sharpness is set too high
Subpixel layout check
Get close to the screen or use your phone's camera at 2–3× zoom on the white bar below. You'll see the subpixels themselves. Compare with the diagrams:
Diagrams are simplified to show the order of subpixels; real layouts vary by panel.
Getting the sharpest picture
- Use the native resolution (check it on the screen resolution page).
- Prefer 100% or 200% OS scaling where the size works for you; fractional scaling can soften some apps.
- Set the monitor's sharpness to its neutral value (often 0, 50 or the default) and adjust until halos vanish.
- On TVs used as monitors, choose PC or Game mode and a 4:4:4-capable HDMI input.
- On Windows, run "Adjust ClearType text" and pick the clearest samples.
Questions people ask
Why is text blurry on my monitor?
The most common causes are: running below the panel's native resolution, OS scaling at a fractional value such as 125% or 150% with apps that don't support it, a sharpness setting that is too high (halos) or too low (soft), chroma subsampling over HDMI to a TV (4:2:2 or 4:2:0), or ClearType tuned for the wrong subpixel layout.
What is a subpixel layout and why does it matter?
Most LCDs arrange each pixel's subpixels as red, green, blue from left to right. Some panels use BGR, and many OLEDs use triangular or pentile layouts. Font smoothing like ClearType assumes RGB stripes; on other layouts, text can show coloured fringes.
What is chroma subsampling?
To save bandwidth, a signal can send colour at lower resolution than brightness (4:2:2 or 4:2:0). Photos look fine but coloured text gets smeared fringes. For a PC, you want RGB or YCbCr 4:4:4. TVs often need PC or Game mode and a specific HDMI port for 4:4:4.