Test pattern
Two classic patterns drawn at your screen’s native resolution. Open them full screen, or download a PNG to show on a TV.
Color bars
Use the three narrow bars at the bottom right: raise brightness until the right one is just visible while the left one stays black.
Test card
The circle should be round, the red edge visible on all four sides, and the line groups crisp. The numbers in the middle are your screen’s real pixels.
More screen tools
Dead pixel test
Five colors, one at a time, to find dead and stuck pixels.
Refresh rate test
See your screen’s real Hz and spot stutter.
Screen test
Gradients, black level, uniformity, gamma and sharpness.
Zoom light
A soft, warm light for video calls from a spare screen.
Background images
Plain color PNGs for desktops, phones and 4K.
Questions
What are SMPTE color bars?
A broadcast test signal with bars at 75% intensity and a strip of near-black bars. This is an RGB version for computer and TV screens.
How do I show a test pattern on a TV?
Open this page in the TV’s browser, cast a browser tab, or download the PNG at your TV’s resolution and open it from a USB stick.
Why does the test card show a different resolution than my monitor?
It shows the pixels your browser draws, which include display scaling. On a 4K screen at 150% scaling, a full-screen window is still 3840 × 2160 device pixels.