Red Pixel Test
Display a full-screen red field to find pixels that remain dark, show the wrong color, flicker, or reveal uneven red-channel reproduction.
A controlled red screen makes missing or abnormal red subpixels and visible color-uniformity differences easier to locate. Clean the panel, open the red test full screen, inspect the center and edges from a normal distance, then move closer only to confirm a suspicious point.
What does this test measure?
A controlled red screen makes missing or abnormal red subpixels and visible color-uniformity differences easier to locate.
Why is this test important?
Display a full-screen red field to find pixels that remain dark, show the wrong color, flicker, or reveal uneven red-channel reproduction.
How do you run the test?
Clean the panel, open the red test full screen, inspect the center and edges from a normal distance, then move closer only to confirm a suspicious point.
How should results be interpreted?
A black, green, blue, white, or flickering dot that stays in the same position across repeated checks may indicate an abnormal pixel or subpixel.
Normal and problematic results
A black, green, blue, white, or flickering dot that stays in the same position across repeated checks may indicate an abnormal pixel or subpixel.
Technical limitations
The page cannot determine whether the cause is the panel, scaling, image processing, cable, graphics output, or temporary pixel behavior.
Why can the score decrease?
Unstable measurements, denied permissions, unsupported browser APIs, background load, power saving, or an incomplete test can affect the result. When a score changes, the result screen explains the reason.
What should you do if a problem is found?
Repeat at native resolution with another cable, port, browser, and device; follow the manufacturer's pixel policy if the mark remains.
Example Result Explanation
Frequently Asked Questions
Why test with a full red screen?
A solid red field drives the red subpixel of every pixel at once and leaves green and blue dark. Any pixel whose red element has failed stands out immediately as a dark dot that the mixed colours of normal use would hide.
I see a dark dot only on red. What does that mean?
That points to a partially failed pixel rather than a fully dead one: the red subpixel is out while the others still work. On white it will show as a faint cyan tint, which is far harder to notice.
Red looks uneven towards the edges. Is the panel faulty?
Mild variation across a large red field is normal, particularly on IPS panels and when you look from an angle. Judge uniformity from directly in front and compare with the grey test, which shows genuine unevenness more reliably.