Color Screen – Red, Green, Blue and Custom
Pick a color and press F to fill your screen with it. Red, green and blue each light a single subpixel, which makes them the surest way to find a stuck or dead subpixel. Prefer an automatic run? The dead pixel test cycles through them for you.
Click to fullscreen or press F/Space
Pick a color
Resolution Settings
Presets
Keyboard Shortcuts: Press F or Space for fullscreen, ESC to exit
Found a stuck pixel? Try to revive it with the Dead Pixel Fixer
How to Use This Tool
What is this Test?
Every pixel on an LCD or OLED screen is made of three subpixels: one red, one green and one blue. A full-screen primary color switches on only one of those three across the whole panel, which is why it is the most reliable way to find a single faulty subpixel. On pure red, a stuck green or blue subpixel shows up as a bright green or blue dot. A dead red subpixel shows up as a dark dot, because the red light at that spot is missing. A white screen lights all three subpixels and a black screen lights none, so those two screens can hide a defect that only affects one color channel. This page lets you switch between the primaries, the mixed colors and any custom color without leaving the page.
What Each Color Reveals
- Red, green and blue: each lights a single subpixel channel. Cycle through all three to check every subpixel on the panel. A dot that stays visible in all three is usually a dead pixel. A dot that only appears on one or two colors is a stuck subpixel, which can sometimes be revived.
- Yellow (red + green): useful for spotting a dead blue subpixel inside an otherwise bright area, and for checking yellow-green tint on cheaper panels.
- Pink, purple and orange: mixed colors that make tint and uniformity problems easier to see than pure primaries. A patch that looks more salmon than pink, or a purple that drifts toward blue at the edges, points to uneven color across the panel.
- Custom color: enter any hex value to match a brand color, a chroma-key shade or a color you are calibrating against.
Reading the Results
- Color shifts toward the edges: common on IPS and VA panels viewed from an angle. Sit straight in front of the screen before judging uniformity.
- Clouding or blotches: visible as darker or lighter patches on green and blue especially. A mild amount is normal on large LCD panels, strong patches visible in normal content are worth a return.
- Oversaturated primaries: wide-gamut monitors show #FF0000 as a deeper red than an sRGB monitor does. That is the panel, not a defect. Switch the monitor to its sRGB mode if colors look neon in everyday use.
- Banding in mixed colors: steps in what should be a flat color usually mean a 6-bit panel with dithering, or a color profile that clips values.
Using the Screen as a Backdrop
- Chroma key: a green or blue screen behind a small object or a hand can be keyed out in OBS, Premiere or DaVinci Resolve. A monitor is too small and too reflective to replace a fabric green screen behind a person.
- Fill light: a bright color on a large monitor adds a colored rim or fill light for photos and video calls. It is weak compared with a real light, so keep the screen close to the subject.
- Product photos and mockups: download the color as a PNG at the exact resolution you need, for example 3840 x 2160 for a 4K background.
Testing Tips
- •Clean the screen first. Dust looks exactly like a dead pixel on a bright color, but it moves when you wipe it.
- •Run through red, green, blue, then white and black. Together they check every subpixel in both its on and off state.
- •Use full screen (F or Space) so browser bars and taskbar do not hide the edges of the panel.
- •Look from about 30 to 50 cm, then lean in to check any spot you noticed. Use your phone camera zoom to confirm whether a dot is one subpixel or a whole pixel.
- •Write down the position of any defect (for example "15 cm from the left, 4 cm from the top") before you exit full screen, so you can find it again or show it to support.
- •If you are sensitive to flashing light, avoid switching rapidly between bright colors in a dark room.
Keyboard Shortcuts
How this test works
Each color button sets the whole panel to one exact hex value, and full screen removes everything else from view. The presets are the pure primaries (#FF0000, #00FF00, #0000FF) plus mixed colors; Custom accepts any color. A link with ?color=red or similar opens the page on that color, and Download saves the current color as a PNG at the resolution you set.
Pro Tip: A stuck subpixel is lit in one color all the time, and a dead one never lights. Stuck subpixels can sometimes be freed by rapidly cycling colors over the spot with the Dead Pixel Fixer for 10 to 30 minutes. Dead pixels cannot be fixed in software, so check how many your manufacturer allows under its pixel policy before you start a warranty claim.
Frequently Asked Questions
Which colors should I use to find dead pixels?
Red, green and blue each light only one subpixel, so together they check every subpixel on the panel. Add white to find dead pixels, which show as black dots, and black to find stuck or hot pixels, which show as bright dots.
What is the difference between a dead and a stuck subpixel?
A dead subpixel never lights, so it leaves a dark spot on its own color. A stuck subpixel is always lit, so it shows up as a colored dot on the other colors and on black. Stuck subpixels can sometimes be freed with the Dead Pixel Fixer.
Why does pure red look orange or neon on my monitor?
Wide-gamut monitors can show a deeper red than the sRGB standard most websites assume, so #FF0000 looks more saturated than intended. That is not a defect. Switch the monitor to its sRGB mode if colors look exaggerated in everyday use.
Can I use the green or blue screen for chroma key?
For small objects or hands in front of the screen, yes, and most editing apps will key it out. A monitor is too small and too reflective to replace a fabric green screen behind a person.
How do I get a custom color or a color image?
Choose Custom and pick any color, or type its hex code. The Download button saves the current color as a PNG at the resolution you set, for example 3840 x 2160 for a 4K background.
Can I link straight to one color?
Yes. Add ?color= to the address with red, green, blue, yellow, orange, pink or purple, for example /color-screen?color=green, and the page opens on that color.
Written by R. Ottens, front-end developer & image editing specialist.