How our screen checks work
ScreenCheckup sends a chosen color pattern to your browser. You look at the physical display and record what you notice. The website does not read the light coming from your panel.
Choose a check for the screen type or symptom
- LCD screen test: compare familiar colors and gray levels on an LCD display.
- OLED / AMOLED screen test: compare colors and low gray fields on an OLED panel.
- Dead pixel check: compare the same point on white, black, red, green, and blue.
- LCD backlight check: compare black and near-black at your normal brightness and viewing angle.
- OLED image retention check: compare gray levels and solid colors for a fixed shape.
Exact digital patterns
These are RGB code values sent to the browser, not measured brightness. Gray percentages are rounded digital channel levels: for example, 5% uses RGB 13, 13, 13. Display settings, color management, viewing angle, and room light affect what you see.
| Pattern | RGB | Hex |
|---|---|---|
| White | 255, 255, 255 | #ffffff |
| Black | 0, 0, 0 | #000000 |
| Red | 255, 0, 0 | #ff0000 |
| Green | 0, 255, 0 | #00ff00 |
| Blue | 0, 0, 255 | #0000ff |
| Yellow | 255, 255, 0 | #ffff00 |
| Cyan | 0, 255, 255 | #00ffff |
| Magenta | 255, 0, 255 | #ff00ff |
| Orange | 255, 140, 0 | #ff8c00 |
| Purple | 128, 0, 255 | #8000ff |
| Violet | 143, 0, 255 | #8f00ff |
| 5% gray | 13, 13, 13 | #0d0d0d |
| 10% gray | 26, 26, 26 | #1a1a1a |
| 20% gray | 51, 51, 51 | #333333 |
| 50% gray | 128, 128, 128 | #808080 |
Make an observation repeatable
- Clean the screen according to the device maker’s instructions. Use a comfortable brightness and avoid reflections.
- Enter fullscreen, or use the viewport fallback if your browser does not allow fullscreen. Browser bars can remain in fallback mode.
- Compare several patterns. Write down the physical location, brightness setting, room light, and viewing angle.
- Repeat during normal use. If you need a photograph, use another camera: screenshots do not capture a physical panel defect.
How to compare computer screens
Open the same visual patterns on each display, use each screen’s normal viewing conditions, and note the settings and visible differences. This is a repeatable side-by-side observation, not a calibrated measurement: a browser cannot normalize brightness, color accuracy, or panel uniformity across devices.
What we verified in the application
On , desktop Chrome checks covered fullscreen entry and exit, color switching, keyboard focus, local record persistence, copying, and deletion. A denied-fullscreen path and touch layouts at 390 × 844 and 844 × 390 were also checked. Those phone layouts were browser simulations; they are not real Android or iPhone tests.
These are software interaction checks, not panel laboratory measurements or tests of a particular device’s hardware condition.
What this cannot establish
The tool cannot measure physical luminance, Delta E, HDR performance, or the number of damaged pixels. It does not calibrate the display or produce an overall screen score. It cannot identify the cause of every visible mark, distinguish temporary retention from permanent wear in a single session, repair a panel, or certify warranty eligibility.
Our editorial policy explains how we use manufacturer guidance. For a problem with the website, contact ScreenCheckup; hardware questions belong with your device maker.