New & Used Screen Inspection Checklist
Use this checklist when checking a new monitor before its return deadline, or a used phone, laptop or monitor before a purchase. It covers visible screen observations, not a complete device inspection or a professional certification. No download or account is required for the color test.
Open the nine-color screen test →
1. Prepare the display you are actually checking
- Open the test on that device. For an external monitor, move the browser window onto that monitor and inspect each display separately.
- Clean according to the manufacturer’s instructions. For example, see Apple’s cleaning guidance for Apple products. Use comfortable brightness and reduce glare; avoid pressing, rubbing or heating the panel.
- On a computer, check the operating system’s display settings and use the panel’s native resolution where available. Our screen information reports browser values; it cannot certify the physical resolution or refresh rate.
- Note the exact model, seller’s return deadline and applicable return or pixel policy. Ask the seller before a purchase if the terms are unclear.
2. Inspect the same location across several colors
Start the solid-color test. Let the hints disappear so they do not cover an area you want to examine. Click, tap, swipe or use the arrow keys to change color.
| Background | Look for | What to do next |
|---|---|---|
| White and other bright colors | A fixed dark dot or irregular dark mark | Clean safely and recheck the same location on red, green and blue |
| Black | A persistent bright or colored dot | Compare all primary colors; black alone does not identify the fault |
| Red, green and blue | A dot that differs from the surrounding color | Note which backgrounds reveal it and which hide it |
| Gray | Broad patches or uneven-looking areas | Reduce reflections and compare viewing angles; this is not a calibrated uniformity measurement |
Work across the center, edges and corners. Check all nine backgrounds; a quick glance at one color can miss a mark that blends into it. The enlarged simulated examples explain common appearances without claiming to diagnose your display.
3. Record what was covered
A browser test only lets you inspect areas that actually display the color. Browser controls, notches, rounded corners and status areas may remain outside it. Record whether you used full-screen mode or only the browser viewport.
For an iPhone, follow the Safari screen test guide. Try portrait and landscape and note the visible coverage yourself. A Home Screen shortcut does not guarantee that every physical pixel is checked.
4. Photograph a persistent mark
Use another phone or camera. Take one wider photo to show the location, then close-ups of the same spot on white, black and the primary colors. Keep the original files. A screenshot cannot capture a physical defect in the panel.
Fill in the observation record: model, date, system and browser, brightness, covered area, checked colors, mark location and photo filenames. Record what you see rather than labeling the device PASS or FAIL automatically.
5. Choose the next step before the deadline
- No unusual mark noticed: keep your notes if useful. This is your observation, not a guarantee that the panel is defect-free.
- A mark remains after cleaning and comparing colors: contact the seller or manufacturer with your notes and photos. Check the policy for your exact model and region. Dell’s pixel guidelines illustrate why bright and dark pixel policies differ; do not apply one manufacturer’s terms to another device.
- A colored dot suggests a stuck subpixel: the optional stuck pixel experiment requires acknowledging its flashing-content warning. Recovery is uncertain, and it cannot repair physically failed pixels. Do not let experimentation make you miss a return deadline.
What this check does not cover
This tool does not automatically detect defects, test touch sensitivity, measure color accuracy or certify refresh rate. A used-device purchase also needs checks beyond the display, such as battery, ports, locks and ownership. This checklist does not verify those items.
Start the screen check → · Save your observations · Understand the repair limits
Screen inspection FAQ
Does this checklist certify that a screen is defect-free?
No. This is a manual observation checklist. It cannot automatically diagnose the panel, check hidden screen areas or certify display quality.
Should I use a screenshot as evidence of a bad pixel?
Use another phone or camera to photograph the physical display. A screenshot records the generated image, not a physical pixel fault.
Does a pixel defect automatically qualify for a return?
No. Return and warranty terms depend on the seller, exact model and region. Check the applicable policy and deadline before deciding.