MONITOR TEST, DEAD PIXEL & OLED CHECK

Let the monitor warm up for roughly 20 to 30 minutes if you are judging uniformity or tonal behavior. Clean only according to the manufacturer instructions, with the display powered off, so dust and dried droplets are not mistaken for pixel defects. Set the computer to the panel's native resolution and a supported refresh rate. Disable temporary magnification, browser zoom, and operating-system color filters. Use 100% browser zoom for fine-line patterns.

• Use the same cable and port planned for normal use.
• Inspect from the normal seating distance before moving close.
• Test SDR and HDR separately; a normal web page is usually an SDR stimulus.
• Take notes before changing a control so improvements can be reversed.

Use normal room lighting for pixel defects, sharpness, geometry, gradients, and everyday uniformity. Reflections should be controlled, but a completely dark room can exaggerate small brightness differences that never appear in use. For LCD backlight bleed, local-dimming blooming, and deep-black inspection, dim the room and allow your vision to adapt for a few minutes. Keep monitor brightness near the level you actually use before trying a brighter diagnostic comparison.

Start with white, black, red, green, and blue for a dead pixel check. Continue with 5% and 50% gray, gradients, black-level steps, white saturation, sharpness, geometry, viewing angle, blooming, and motion. Full screen removes page chrome and makes edge defects easier to see. In full screen, use the arrow controls or tap the pattern to advance; pause the slow color cycle whenever a point needs closer inspection.

An LCD pixel typically combines red, green, and blue subpixels. A completely dark point on white and primary-color fields may be called a dead or dark pixel. A point that remains one color can be a stuck subpixel. A bright point visible on black is often described as a bright or hot pixel. OLED pixels are self-emissive, but the same full-field color method helps reveal subpixels that are inactive, permanently lit, or uneven.

Dust on the outer surface changes with focus and may disappear when viewed from another angle. A scratch catches reflected light. Debris trapped inside an LCD layer can cover several pixels with an irregular shape. A software cursor, overlay, compression artifact, or graphics error can appear in a screenshot. A true panel defect usually stays at the same physical coordinate while content, applications, inputs, and the monitor menu change.

A visible defect does not automatically meet replacement criteria. Policies can distinguish bright pixels, dark pixels, subpixels, clusters, panel size, monitor line, and normal viewing distance. Premium product lines may allow no bright pixels while permitting several dark subpixels; other lines use different thresholds. Check the current policy for the exact model, region, purchase date, and warranty program instead of relying on a generic ISO reference.

Uniform gray fields remove picture detail and make spatial variation easier to see. Dirty screen effect, or DSE, can resemble faint smudges, darker patches, or vertical bands during sports and camera pans. Mura is a broader term for nonuniform luminance or color. LCD backlight construction, panel pressure, viewing angle, compensation, and OLED pixel aging can all contribute.

A smooth grayscale ramp should transition without abrupt stripes, false color, or large flat regions. Color gradients can reveal channel clipping and posterization. Banding can originate in a low-bit-depth source, compressed image, browser rendering, operating-system output format, graphics card, cable path, monitor processing, or panel. Temporal dithering may make an apparently smooth ramp shimmer under a camera even when it looks smooth to the eye.

The near-black grid shows RGB values 1 through 20 against black. The first few may be extremely subtle, especially on OLED, but more steps should gradually become visible. If many merge into black, shadows may be crushed by an incorrect range, black equalizer, gamma mode, or dark-room adaptation. Raising black controls until every patch is obvious can wash out the background and reduce perceived contrast.

Fine checkerboards and alternating lines should remain crisp at native resolution and 100% browser zoom. Softness can indicate non-native resolution, operating-system scaling, browser zoom, chroma subsampling, image processing, or an analog path. Bright halos beside dark lines suggest excessive sharpness or ringing. Moire in a phone photograph does not necessarily exist to the eye because two pixel grids interfere.

Image retention is a temporary remnant that fades after varied content or the manufacturer's normal compensation process. Burn-in is persistent uneven wear that remains visible after the panel has had time to recover. Common shapes include taskbars, channel logos, game HUDs, browser edges, and static application panels. A gray OLED test often reveals these shapes more clearly than saturated colors.

Small output differences become proportionally visible near black, so OLED vertical bands often emerge between 2% and 10% gray. Some new panels change during early compensation cycles. Severe bands that remain visible in ordinary dark scenes are more important than faint structure visible only in a dark room on a 5% field. Camera exposure can amplify banding far beyond the visual impression.

Full-field white and saturated colors are static high-area stimuli. Use moderate device brightness, keep each inspection purposeful, pause when taking notes, and leave the test when finished. Automatic brightness limiting may dim a large white field after a moment even though the browser color has not changed. That is panel power and thermal management, not a failed test.

Follow a moving block with your eyes rather than staring at one fixed point. A soft trail can come from sample-and-hold eye-tracking blur, pixel response, or both. Dark smearing is common when some VA transitions are slow. A bright or colored inverse trail can indicate overdrive overshoot. Increase speed gradually and compare the same row under each monitor overdrive mode.

The displayed refresh estimate is derived from requestAnimationFrame timing. It can confirm that the browser is presenting near a common rate such as 60, 120, 144, or 240 Hz, but background throttling, system load, compositor behavior, variable refresh, and rounding affect it. It does not prove the panel accepted every frame or measure scanout, input lag, gray-to-gray response, or motion-picture response time.

The blooming pattern places small white targets on black. Mini-LED and other local-dimming displays may illuminate zones larger than the target, creating a halo. More zones and better algorithms can reduce the effect, but camera exposure and off-axis viewing exaggerate it. Compare center and corner targets from the normal seat and with local dimming settings that you actually use.

View the neutral and colored blocks from the center, then move horizontally and vertically while keeping distance similar. TN panels often change strongly with vertical angle, VA panels can shift gamma off-axis, IPS panels generally preserve color better but may show glow, and OLED often maintains contrast while color or near-black behavior can still change.

Run the monitor test within the return window using normal brightness and viewing distance. Prioritize dead or bright pixels, severe uniformity, obvious tint, unstable signal, cropping, and artifacts visible in ordinary work or games. Test every physical input you plan to use, verify native resolution and advertised refresh options, and check sleep and wake behavior separately.

Ask the seller to reset picture settings and allow enough time for inspection. Use solids for pixels, gray for wear and DSE, black for bleed or OLED raised blacks, gradients for banding, geometry for cropping, and motion for obvious response artifacts. Check the bezel, coating, ports, stand, power supply, and menu buttons. View the monitor's own menu because it bypasses the computer signal.

Write down the pattern, color or gray level, exact location, normal viewing distance, room condition, monitor preset, brightness, input, cable, and whether the issue appears in the on-screen menu. Export the local report and add photographs only when they represent the visual result. Include a normal-content example when possible.

The screen information panel reports CSS screen dimensions, browser viewport, device pixel ratio, color depth exposed by the browser, and an estimated animation cadence. CSS dimensions may differ from physical panel pixels because of operating-system scaling. Device pixel ratio describes the mapping used by the browser, not panel pixel density, subpixel layout, or effective sharpness.

Calibration requires a target, a measurement instrument such as a colorimeter or spectrophotometer, controlled software, and a correction process. Visual patterns can help set obvious clipping, scaling, and geometry, but human vision adapts to brightness and color. Two displays can make the same web color look different, and neither appearance proves numerical accuracy.

Test patterns are drawn in the browser and no image of your display is captured or uploaded. The exported JSON contains browser-visible values, marked pattern names, and notes. Full screen requires a user action and can be exited through the visible control or the browser's standard Escape behavior.