Dead pixel vs stuck pixel: the quick explanation
A dead pixel often looks persistently dark, while a stuck pixel or subpixel may stay red, green, blue or another fixed colour instead of following the image. A bright pixel may remain lit when the surrounding screen is black. These names describe symptoms; appearance alone does not establish the exact electrical fault.
The practical question is whether one physical screen location repeatedly behaves differently across several backgrounds. Run the Dead Pixel Test to compare solid colours, then use the checks below to separate a likely pixel anomaly from surface contamination or damage.
What a pixel and subpixel are
A pixel is a small picture element in a display. Many panels build each pixel from red, green and blue subpixels whose contributions combine into the visible colour. Subpixel arrangements and display technologies vary; not every panel has the same layout or controls light in the same way.
Consequently, a problem affecting one subpixel can change a dot’s colour without making the entire pixel black. Browser scaling also means one CSS pixel is not necessarily one physical panel pixel. A solid background is useful because it removes image detail that might otherwise conceal the anomaly.
What a dead pixel usually looks like
“Dead pixel” commonly refers to a pixel that does not emit or display the expected light and often appears dark on bright backgrounds. Look for a tiny dark point on white and several other colours, remaining in the same place as the background changes. It may blend into black. Different display technologies and failure modes can produce different symptoms, so a dark dot is not proof of one particular hardware failure.
What a stuck pixel usually looks like
A stuck pixel or subpixel may remain at one state, producing persistent red, green, blue or another incorrect colour. A red dot might blend into a red screen yet stand out on black or cyan. Check several backgrounds rather than treating disappearance on one matching colour as recovery. Record whether its appearance changes and whether it stays at exactly the same screen position.
Bright and hot pixels
“Bright” and “hot” are sometimes used for points that remain unusually lit. They may look white or coloured, and the terminology can overlap with stuck-pixel descriptions. Not every bright point has the same underlying cause. Black usually provides the strongest contrast; also compare white and primary colours to see whether the point consistently differs from its surroundings. Reflections can imitate a bright dot, so rule those out too.
What a subpixel defect can look like
If one colour component does not respond correctly, a pixel may look tinted rather than completely dark or bright. It might appear wrong on white or a mixed colour but less obvious on a primary background. Inspect the same point across the whole sequence. You can describe the observed mismatch without claiming to know which internal component failed; a visual browser test cannot confirm that diagnosis.
Why different background colours reveal different faults
Contrast changes what is visible. A dark point can disappear into black, while a bright point becomes obvious there. Colour backgrounds change the expected subpixel contributions, giving another way to compare a suspicious location. No single colour rules out every defect. Keep brightness and viewing conditions consistent while comparing; changing settings midway can make a small difference harder to interpret.
How to test a screen before drawing conclusions
Start with a clean display in comfortable lighting without strong reflections. Inspect it straight on, at a distance where small marks are visible without strain. Scan systematically in rows or sections so you cover the entire surface, including edges and corners. Pause on each background instead of cycling quickly. Let the test controls fade so their area can also be inspected; tap or click to reveal them again.
Step-by-step: use the Testpartout Dead Pixel Test
- Clean the display carefully using the manufacturer’s instructions.
- Open the Dead Pixel Test on the screen you want to inspect.
- Press “Start Dead Pixel Test”.
- Use fullscreen where supported. If unavailable, the test fills the browser window.
- Look across the entire screen on black.
- Choose Next and repeat on white.
- Inspect red, green and blue carefully.
- Continue through gray, cyan, magenta and yellow.
- Note whether a suspicious dot remains in exactly the same physical location.
- Use Previous and Next to repeat suspicious colours before drawing conclusions.
- Finish the test and choose the answer that matches your observation.
Left and right arrow keys also change colours on desktop. Normal browser fullscreen exit remains available; leaving fullscreen returns to the page. Outside fullscreen, use Finish test. The question “Did you notice any suspicious pixels?” offers clear, suspicious and unsure choices. It reflects your observation, not an automatic diagnosis.
How to interpret black, white, red, green and blue
- Black: look for points that stay bright or coloured. Broad glow or edge light is a different symptom from an isolated dot.
- White: look for dark points, tinted dots and uneven areas. A larger patch need not be a pixel defect.
- Red, green and blue: compare primary-colour behaviour. Note which backgrounds make the same point look wrong and which conceal it.
These are observation clues, not electronic measurements of the panel. A dot that looks black on red alone cannot establish whether an entire pixel or one subpixel is affected.
Why gray, cyan, magenta and yellow also help
Gray can make subtle brightness or uniformity differences easier to notice than maximum white or black. Cyan combines green and blue, magenta combines red and blue, and yellow combines red and green in the browser’s colour model. These backgrounds offer additional contrast for colour-specific anomalies. They do not isolate or measure physical subpixels directly: colour profiles, display processing and panel design influence the light you actually see.
Dust or dirt versus a pixel defect
Dust and smudges sit on the surface and can look like dark pixels. Turn the display off and inspect the same spot under gentle reflected light. Clean only according to the maker’s guidance, without scraping, strong pressure or applying liquid directly to the panel. Surface contamination may move or disappear after cleaning.
A pixel anomaly stays aligned with the pixel grid at the same physical position across backgrounds. Fixed dirt can also stay in place, so persistence alone is not enough; combine the screen-off check, safe cleaning and repeated colour comparisons.
Scratches and panel damage versus a pixel issue
Scratches or coating damage may remain visible with the display off and change appearance with reflections. Pressure marks, cracks and damaged areas can span many pixels or form irregular shapes. An isolated, grid-aligned dot is a different pattern, but visual size is not definitive evidence of its cause. Do not press on a mark to see whether it changes. Persistent surface or panel damage deserves manufacturer evaluation.
What to do if you find a suspicious pixel
Note its position, approximate size and the backgrounds where it is visible. Return to the Dead Pixel Test and compare that exact location again after safe cleaning. If the anomaly persists, describe the symptom to the manufacturer rather than assigning a definite fault yourself.
So-called pixel-fixing techniques appear online, but results are not guaranteed. This test does not attempt repairs. Avoid rapid flashing tools and aggressive rubbing, pressure, heat or opening the monitor; such methods can create risks or damage the display. Retesting and supported service guidance are safer next steps.
When to repeat the test
Repeat if you were distracted, missed part of the screen, found a mark that may be dirt, or are unsure whether the location stayed fixed. Compare the same colours under similar lighting and settings. If the mark appears only within one app, check whether it follows that app’s content when moved; content artefacts differ from a fixed panel location. A clear pass means you noticed no anomaly, not that every pixel is certified fault-free.
Warranty and manufacturer considerations
Warranty treatment can vary by manufacturer, display model, defect type, number and location of affected pixels, region and policy. Check the exact manufacturer’s current terms for your display; there is no universal replacement threshold to infer from this guide. A retailer’s return policy may differ from the warranty. If the screen is new, check applicable deadlines promptly and ask support what evidence they require. Keep your purchase details and observation notes available.
Limitations and privacy of browser-based testing
Testpartout displays nine deliberate solid colours locally in your browser. It does not automatically detect defects, inspect panel electronics or determine whether a particular pixel is definitely dead or stuck. Restricted fullscreen can leave areas outside the browser untested. Scaling, viewing angle, brightness and colour processing also affect observation.
No screenshot or inspection result is saved or uploaded; your answer exists only in the current page state. With analytics consent, limited interaction events may be sent, not screen images or inspection data. This is a visual check, not a certification, colour-calibration tool or warranty decision.
Frequently asked questions
What is the difference between a dead pixel and a stuck pixel?
A dead pixel often stays dark; a stuck pixel or subpixel may stay coloured or bright. These symptoms do not identify every possible hardware fault.
How can I tell if a pixel is dead?
Look for a persistent dark point on several bright backgrounds after ruling out dirt. That suggests an anomaly, but a browser cannot confirm its exact cause.
What does a stuck pixel look like?
It may look like a tiny fixed-colour dot that does not match the surrounding image, becoming clearer on contrasting backgrounds.
Can a stuck pixel be red, green or blue?
Yes. A stuck colour component may produce persistent red, green or blue; other fixed bright colours are also possible.
Why should I test with different colours?
Each background changes contrast and expected colour output. A matching background can hide an anomaly that another colour reveals.
Can dust look like a dead pixel?
Yes. Check with the screen off, clean safely according to manufacturer instructions, then compare the same location again.
Can a browser automatically detect dead pixels?
This test cannot. It supplies backgrounds for human inspection and has no access to the physical panel’s light output or electronics.
Can stuck pixels be repaired?
There is no guaranteed repair from this test. Follow manufacturer support guidance; avoid risky pixel-fixing methods.
Should I return a monitor with a dead pixel?
Check the retailer’s return terms and the manufacturer’s policy for your exact model and region. A suspicious dot alone does not establish eligibility.
Does Testpartout save anything from my screen test?
No screen image, display inspection data or visual answer is saved or uploaded. Consent-controlled usage events are separate from your inspection.