This page opens on plain white, #ffffff, the brightest color a screen can show. Space or → steps to a warm white, a cool white and then black; on a phone or tablet in full screen, tap the color for the Next color button. Press Full screen so no browser bars are left, and turn the brightness up in the device’s settings, since a web page can’t raise it.
A bright light from any screen
A full white screen is the quickest light you have: to find something under a desk, read a label in a dim room or light a document you are photographing. Pick Warm white if the light is in someone’s face or the room is dark; it is softer than pure white. The page asks the browser to keep the display awake while it is full screen, but Low Power Mode or battery saver can still dim it.
If you need a light box for tracing, use the tracing light box page, which ignores taps so your hand can rest on the glass while you draw. For lighting your face on a video call, the video call light offers six whites matched to bulb color temperatures.
Find dust and smudges, then clean
- Open the white in full screen and look across the screen from the side, toward a lamp or window. Dust, hairs and specks show as dark dots on white.
- Press Space until you reach Black. Fingerprints, streaks and smears show on a dark screen, so check both.
- Turn the display off before you wipe it. Apple’s cleaning guidance says to disconnect a display from power, wipe it with a soft, dry, lint-free cloth, use only a cleaner meant for screens, never spray it directly onto the screen, and avoid acetone (as of October 2026). Other makers give similar advice in their manuals.
- Switch the screen back on and run through white and black again to see what’s left.
A dot that won’t wipe off and stays put on every color may be a pixel, not dust: the dead pixel test tells them apart.
Checking a projector or a screen’s white
On a projector, show the white full screen and step back. Look for corners that fall off much darker than the center, a color tint across one side, dark blobs that move when you refocus (dust in the light path) and edges that stay soft when the center is sharp. Then switch to black to see how much light the projector lets through when the picture should be dark.
On a monitor or TV, plain white shows tint problems: a pinkish, greenish or yellowish patch, or one side cooler than the other. Turn off Night Shift, Night Light, True Tone and similar settings first. For a fuller check, the monitor test runs gray uniformity fields, banding ramps and black level steps.
The 4 colors on this page
| Color | Code | Light |
|---|---|---|
| White | #ffffff | 100% |
| Warm white | #fff4e6 | 92% |
| Cool white | #f0f5ff | 91% |
| Black | #000000 | 0% |