How to Test a New Monitor: Dead Pixels, Backlight Bleed and More
October 31, 2026 · TrimSwap
Most screen problems are easiest to fix in the first few weeks, while you can still return or exchange the screen. This checklist takes about 15 minutes and only needs a web browser.
Before you start
- Clean the screen with a soft, dry microfiber cloth, so dust isn't mistaken for a dead pixel.
- Let it warm up for 15 to 30 minutes. Some panels look a little uneven when they're cold.
- Use the native resolution and set brightness to the level you'll normally use (turn it up for the bleed test).
- Check the return window and keep the box until you're done.
1. Dead, stuck and hot pixels
Open the dead pixel test and go full screen. It shows black, white, red, green, blue and a few other solid colors, one at a time. Look slowly across the whole screen on each color.
- Dead pixels stay black on every color, and are easiest to see on white.
- Stuck pixels stay one color (usually red, green or blue), and stand out on black.
- Hot pixels stay white or bright, and are easiest to see on black.
2. Backlight bleed and IPS glow (LCD screens only)
Turn off the lights, turn the brightness up, and open the backlight bleed test. Look at the edges and corners from straight in front of the screen.
- Backlight bleed is light leaking in at the edges. It stays in the same place when you move your head.
- IPS glow is a silvery sheen in the corners that shifts or fades as you move. It's normal for IPS panels.
OLED screens have no backlight, so they don't have bleed; skip this step for them.
3. Uniformity and banding
Open a 50% gray screen and then a dark gray screen. Look for patches that are noticeably lighter, darker or tinted, a dirty-looking "smudged" area, or visible stripes. Some unevenness is normal on large screens; it's a problem when you notice it in everyday use.
4. Colors and viewing angles
Look at red, green, blue and white screens, first straight on and then from the side and from above. Colors should look clean and even. A white screen with an obvious pink, green or yellow tint in one area is worth a closer look.
5. Everything else
- Look for scratches or marks on the screen and frame.
- Try every port and button, and check the stand for wobble.
- Listen for buzzing or high-pitched whine, especially at low brightness.
Found a problem?
Take a photo or video that shows the problem as you actually see it (phone cameras exaggerate glow and bleed, so lower the exposure). Then check the seller's return policy and the manufacturer's pixel policy; they vary a lot, so read the one for your exact model. If the screen is within the return window, contacting the seller is usually the quickest fix.