What is the difference between a dead pixel and a stuck pixel?

A dead pixel is permanently turned off and appears as a tiny black dot on a bright white screen. A stuck pixel has one or two color transistors frozen open, appearing as a persistent red, green, or blue dot on a black background.

Can a white screen test fix stuck pixels?

While dead pixels (dead transistors) cannot be revived, stuck pixels can often be fixed by rapidly cycling primary RGB colors. Our built-in 'Stuck Pixel Exerciser' flashes high-frequency color cycles to stimulate the sluggish liquid crystal molecules back into alignment.

How do I check for backlight bleed on my monitor?

Select the Pure Black (#000000) mode, enter fullscreen, and dim your room lights. Look at the edges and corners of the display. Backlight bleed appears as cloud-like yellow or white light leaks escaping from the monitor frame.

Can I use the white screen as a lighting source for webcam video calls?

Yes! Maximizing a pure white screen creates an effective, soft, diffused front fill-light for Zoom, Google Meet, and streaming calls without buying expensive studio ring lights.

⚡ Instant Fullscreen White Screen & Dead Pixel Detector

White Screen Test: Spot Dead Pixels & Backlight Bleed

Open a pure white screen in fullscreen to identify dead pixels, check monitor backlight bleed, clean screen dust, evaluate OLED burn-in, or use as a bright video call fill light in seconds.

⛶ Click or Double-Tap for Fullscreen

Diagnostic Colors & Presets:

Custom:

Active Color #FFFFFF

Resolution 1920 × 1080

Pixel Ratio (DPR) 1.0x

Measured Refresh Rate 60 Hz

White Screen Test

How to Test Your Screen in 3 Steps

Clean Your Display Surface

Before testing, wipe away physical dust and fingerprints using a dry microfiber cloth to avoid mistaking surface dirt for dead pixels.

Enter Fullscreen White Mode

Click Open Fullscreen or double-click the preview area. This fills 100% of your monitor without browser tabs or taskbars.

Cycle Colors & Check Edges

Press the Spacebar or arrow keys to cycle between White, Black, and RGB colors. Look for stuck color dots, black dead pixels, or edge backlight bleed.

The Complete Guide to Display Testing, Dead Pixels & Backlight Bleed

A pure white screen test is the foundational diagnostic tool for computer monitors, smartphone screens, laptops, and television panels. Inspecting your display under uniform illumination isolates manufacturing defects, physical panel damage, and optical imperfections.

Dead Pixels vs. Stuck Pixels: Understanding the Difference

Every modern LCD and OLED display is composed of millions of tiny picture elements (pixels), each containing Red, Green, and Blue subpixels controlled by Thin Film Transistors (TFTs):

Dead Pixels (Black Dot on White): Occur when a transistor fails completely or permanently loses power. The pixel cannot illuminate and remains a permanent black speck on a pure white screen. Dead pixels cannot be repaired by software.
Stuck Pixels (Colored Dot on Black): Occur when one or two subpixel transistors freeze in the 'on' state. They appear as a bright red, green, blue, or yellow dot against dark backgrounds. These can frequently be massaged or unstuck using high-frequency color exercisers.
Hot Pixels: Occur when all three subpixels remain continuously energized, showing as a bright white dot on an otherwise black screen.

Diagnosing IPS Glow vs. Backlight Bleed

When switching your screen to Pure Black (`#000000`) in a dimly lit room:

Backlight Bleed: Caused by physical gaps or uneven bezel pressure allowing the internal LED backlight to bleed around the display borders. It appears as persistent yellow or white light patches that remain fixed regardless of your viewing angle.
IPS Glow: A natural optical characteristic of In-Plane Switching (IPS) panels resulting from light refraction at wide angles. Unlike backlight bleed, IPS glow changes intensity or shifts position as you move your head.

Using a White Screen as a Lightbox or Video Fill Light

Beyond hardware diagnostics, maximizing a white screen turns your laptop, tablet, or monitor into a versatile light source:

Webcam Fill Light: Placing a bright white screen behind your webcam provides soft, diffused facial illumination during Zoom, Google Meet, and video interviews.
Tracing Lightbox: Place drawing paper or blueprints against an iPad or tablet display at maximum brightness to trace outlines easily.
Macro Photography Background: Creates a clean, shadowless pure white infinity backdrop for product and small object photography.

Display Defects & Diagnostic Colors Matrix

Reference guide pairing common monitor defects with their optimal inspection background color and recommended action:

Screen Defect	Best Test Color	Visual Appearance	Resolution / Recommended Action
Dead Pixel	Pure White (#FFFFFF)	Static black speck that never illuminates	Permanent hardware defect; check manufacturer warranty limits
Stuck Subpixel	Pure Black (#000000)	Permanent bright red, green, or blue dot	Run the Stuck Pixel Exerciser for 10-20 minutes to un-stick
Backlight Bleed	Pure Black (#000000)	Yellow/white light pooling along bezel edges	Physical panel assembly flaw; loosen tight bezel screws or RMA
Color Tinting / Uniformity	Pure White (#FFFFFF)	One side looks cooler (blue) or warmer (yellow)	Calibrate monitor color profile with a colorimeter
OLED Burn-in / Image Retention	50% Gray / Red / Magenta	Faint ghost outlines of taskbars or logos	Run display pixel refresh cycle; avoid static UI elements

Frequently Asked Questions

How many dead pixels are covered under manufacturer warranty?

Most consumer monitors comply with the ISO 9241-307 Class II standard, which permits between 2 to 5 dead or stuck pixels per million pixels before a panel is considered defective. Premium brands (like Dell UltraSharp or Apple) often offer 'Zero Bright Dot' warranties that replace panels with even a single stuck subpixel.

How does the Stuck Pixel Exerciser work?

Our Stuck Pixel Exerciser rapidly cycles primary RGB colors at high frequency. This rapid switching repeatedly cycles voltage to sluggish liquid crystal molecules, often freeing stuck subpixel transistors that have become electrically frozen in place.

How do I exit Fullscreen mode?

Press the Escape (Esc) key on your keyboard, press F11, or double-click anywhere on the screen to instantly return to normal windowed mode.

How is the screen refresh rate (Hz) measured?

Our tool tracks browser animation frame timestamps over 60 continuous display cycles using requestAnimationFrame, calculating your monitor's true active refresh rate (e.g. 60Hz, 120Hz, 144Hz, or 240Hz).