The Complete New-Device Screen Test Checklist

Unboxed something new? Spend ten minutes now so you don't regret it later. Run these tests in order, in a dimly lit room, with brightness at maximum, and give the panel five minutes to warm up first — LCD backlights shift slightly in their first few minutes.

Before you start

• Wipe the screen with a dry microfiber cloth so lint isn't mistaken for a defect. If it needs more than that, follow How to Clean Your Monitor or Laptop Screen Safely.
• Set the display to its native resolution. A non-native resolution blurs everything and hides small faults.
• Turn off Night Light, Night Shift, and any blue-light filter — they add a warm tint that will wreck the color checks.
• Keep the box, packaging and receipt until you've finished. Return windows are short and vary by retailer and country; a pixel-policy warranty claim usually stays open much longer than the return window does.

1. Dead and stuck pixels

Open the Dead Pixel Test and step through every solid color. Watch for any dot that's the wrong color. A dot that stays black is dead; a dot locked on one color is stuck.

Look at the screen from roughly arm's length, then move in to about 30cm and sweep in a slow grid pattern — corners last, because that's where your eye naturally skips. Red, green and blue frames matter most: a single failed sub-pixel shows up as a colored dot on one frame and disappears on the others. If you're unsure what you've found, Dead vs Stuck vs Hot Pixels walks through the differences.

2. Dark-screen defects

Switch to the Black Screen and look for:

• Backlight bleed — cloudy light at the edges (LCD only).
• Dust or debris trapped under the glass.
• Bright (hot) pixels glowing against the black.
• IPS glow — a broad silvery haze in the corners that shifts or vanishes when you move your head. That's a property of IPS panels, not a fault; see Backlight Bleed vs IPS Glow before you decide to return anything.

Do this step with the room lights off. In a bright room you will see almost nothing; in a pitch-dark room you'll see flaws you would never notice in normal use. Judge it at the brightness you'll actually use.

3. Bright-screen defects

Switch to the White Screen and look for dark dots, smudges, scratches and yellow or pink tint patches. Dust under the glass is far easier to spot here than on black. A fleck that doesn't change color as you cycle frames is debris or a physical mark, not a pixel fault.

4. Uniformity

Run the Brightness Uniformity Test. Compare the center to the four corners — big differences mean uneven backlighting. Mid-grey is the most revealing shade: on a full white field your eye adapts and evens things out, but on grey, blotchy patches (mura) and darker bands stand out. Some falloff toward the corners is normal on every LCD. A distinct patch with an edge to it is not.

5. Color and banding

Use the Greyscale Test and Color Gradient Test to check for banding and tint shifts. Every step of the greyscale should look neutral — if the dark end drifts blue or the bright end drifts pink, the panel's white balance is off. Gradients should blend smoothly; visible stripes mean color banding, which is often a signal or settings problem rather than a bad panel.

Finish with the Gamma Test to confirm mid-tones aren't crushed or washed out.

6. Motion (monitors and TVs)

Confirm your panel hits its rated speed with the Refresh Rate Test — a 144Hz monitor plugged in with the wrong cable or left on a default profile will often be running at 60Hz until you change it. Check for trails with the Ghosting Test, and watch for horizontal splits with the Screen Tearing Test.

7. Viewing angle

Step to one side and check the Viewing Angle Test. TN panels shift heavily off-axis, VA panels lose contrast and gain a color wash, IPS and OLED hold up best. On a large screen this matters even head-on, because the edges are already at an angle to your eyes.

What counts as a defect?

Manufacturers tolerate a few dead pixels. The pixel-fault classes in ISO 9241-307 are the usual reference point, and the class most consumer panels are held to allows a small number of faults per million pixels rather than demanding none — a 4K screen has more than eight million pixels, so one or two stuck sub-pixels often won't qualify for a claim. Only your manufacturer's own published pixel policy tells you the actual threshold, and it differs by brand, by product line, and sometimes between a monitor and the laptop it's built into. Check it before you call; Dead Pixel Warranty Policies, Explained covers how those numbers are counted.

Trapped dust, heavy backlight bleed, obvious tint patches, and scratches are a different matter — those are usually grounds for a return under the retailer's own policy, which is often easier to use than the warranty.

If you find something, photograph it now: shoot the black-screen flaws in a dark room with your phone locked to a fixed exposure, and mark small pixel faults with a sticky note at the screen edge. Then start the return while the window is open — the retailer's return period is the leverage you actually have, and it expires long before the warranty does.