For a fixed dark, bright, or colored point, compare the same spot across white, black, red, green, and blue. For bands, tint, or broad patches, compare low and middle gray fields. Black and near-black patterns can help you look for LCD edge light, but reflections and viewing angle can create similar effects.

OLED image retention is a separate question from LCD backlight bleed. Use color and gray fields to see whether a familiar shape stays in the same place; one short browser session cannot prove permanent burn-in. The checker supplies visual references and does not diagnose or repair a panel.

When a browser readout is useful

The resolution report shows CSS dimensions and viewport values exposed by the browser. The refresh sample counts browser animation frames. Aspect ratio and monitor-size calculators use the numbers you enter. None of these tools reads a monitor’s electronics, confirms native pixel resolution, or measures color accuracy.

Repeat the observation under normal conditions

Use a comfortable brightness, your usual viewing position, and the same screen settings when comparing patterns. Turn off a strong color filter only if it changes the view you are trying to compare, and change one setting at a time. A screenshot records the image signal rather than the physical panel.

If a symptom follows a drop or liquid exposure, spreads, comes with unusual heat, or stops touch input, stop testing and contact the device maker. These browser tools cannot determine whether hardware needs service or whether a warranty claim is eligible.