Blue-Channel Display Test
This tool produces one consistent blue field so you can inspect how a panel renders its blue channel. It is most useful as one step in a comparison, not as a stand-alone pass or fail test.
Start at your normal brightness with Night Light, Night Shift, eye comfort mode, and adaptive color disabled. A software color filter can make a healthy panel appear weak or uneven. Clean the surface first so dust is not mistaken for a damaged pixel.
What a Blue Field Can Reveal
Modern panels combine red, green, and blue output. Showing one channel at a time helps separate a channel-specific defect from a mark that affects every color.
Weak or inactive blue subpixels
A tiny dark point here that looks normal on red and green suggests the blue part of that pixel is weak or inactive. If the same point remains dark on white as well, compare all colors before classifying it as a fully dead pixel.
Stuck colored points
A point that stays bright or changes incorrectly while you cycle through the available colors may be stuck. Record its position and repeat the cycle at a lower brightness; reflections and dust usually shift when you change your viewing position, while a pixel defect does not.
OLED wear and retained interface shapes
OLED emitters can age at different rates. Status bars, navigation controls, channel logos, or keyboard outlines may become visible as regions with slightly different output. Confirm a suspected pattern on middle gray and white, because temporary image retention can fade while permanent wear remains repeatable.
Tint and uniformity variation
Compare the center, edges, and corners from your normal viewing angle. A purple region can indicate excess red relative to blue; a cyan region can indicate excess green. On LCD panels, viewing angle and backlight structure can also create variation, so move your head slightly before treating a patch as a fixed panel problem.
Signal-path problems
If the entire field looks wrong only on an external monitor, check the cable, port, graphics color range, HDR mode, and display profile. A failed cable or incorrect limited/full-range setting usually affects a large region or the whole image rather than one stationary pixel.
A Repeatable Five-Pass Protocol
- Baseline: use normal brightness in ordinary room light and note only defects you can see from your regular position.
- Dark-room pass: reduce reflections and inspect the edges, center, and any previously noted location.
- Cross-color pass: use the arrow keys to compare the exact location on red, green, white, gray, and black.
- Settings pass: repeat after disabling HDR, adaptive brightness, and color-temperature filters if they were active.
- Real-content pass: open a photograph, game, or video you normally use and decide whether the observation is visible outside a diagnostic field.
Photographing the result can help document a warranty claim, but phone cameras alter exposure and white balance. Use a photo as a record of location, not as the only proof of severity.
How to Interpret the Comparison
| Observation | Useful follow-up |
|---|---|
| Dark point only on blue | Compare white and cyan; note a possible blue subpixel issue. |
| Bright colored point on black and several colors | Cycle all fields and check whether the point remains fixed. |
| Faint logo or interface outline | Compare middle gray, white, and real content after a rest period. |
| Whole image is purple, cyan, or unusually dim | Disable color filters and check the cable, profile, HDR, and port. |
| Patch changes as your head moves | Account for LCD viewing angle before judging uniformity. |
A variation visible only at maximum brightness in a dark room may not affect normal use. A fixed defect visible from your normal position is more relevant, especially on a new device within its return window.
Using the Display as a Blue Reference Light
A phone, tablet, or monitor can provide a quick blue accent for a close-up photograph, video background, design comparison, or presentation.
This is not a calibrated light source. Brightness limits, panel color profiles, camera white balance, reflections, and viewing angle all change the recorded result. Keep brightness comfortable, avoid staring at a bright field in a dark room, and use professional lighting or a calibrated reference when color accuracy matters.
Frequently Asked Questions
Can this repair a stuck pixel?
A static color cannot repair hardware. Rapid color cycling sometimes changes a temporarily stuck pixel, but it is not guaranteed and will not restore a dead subpixel.
Is this a Windows crash page?
No. It is a plain diagnostic color field and does not imitate an error, scan a computer, or read crash information.
Why does blue look different on two devices?
Panel technology, calibration, brightness, color profile, ambient light, and aging all influence the result. Side-by-side comparison can reveal a difference but does not identify which device is accurate without a calibrated instrument.
When should I contact the seller?
Document the location and compare real content. If a new device has a fixed bright point, several failed pixels, or obvious unevenness during ordinary use, check the seller's return and pixel-defect policy promptly.