How to use the red screen
- Tap Night red for a dim light, or pick any of the other reds.
- Set Brightness; it goes down to 5 %.
- Choose a time under Turn off after if the light shouldn’t stay on all night.
- Press Fullscreen or F. Esc or ✕ leaves fullscreen.
- After an auto-off, Turn on again brings the same light back.
Dim red light for night use and stargazing
NASA’s Night Sky Network notes that your eyes need about 30 minutes to adapt to the dark, that a bright light, a phone included, can undo that for a while, and that stargazers use red lights instead (NASA, “Put On That Red Light”). Keep the red dim and fullscreen, so no bright page parts show; while the red is dim, the buttons that appear over it are red on near-black too. Need the time in the dark? The fullscreen digital clock has a night mode with dim digits.
Make your whole phone screen red
This page reddens its own window. To tint every app on iPhone, open Settings → Accessibility → Display & Text Size → Color Filters, switch them on, choose Color Tint and move the hue fully to red with the intensity up (Apple). The Accessibility Shortcut can switch the filter with a triple-click, and Reduce White Point in the same menu dims further. Android phones offer similar filters under different names, depending on the maker. This page is the option with no settings to change back afterwards.
Night red and the 5 % brightness floor
Night red is #7F0000 at 30 % brightness, which shows #260000. Going down the slider, it becomes #190000 at 20 %, #0D0000 at 10 % and #060000 at 5 %. The slider dims the color the page draws, while your device setting dims the backlight, so use both for the dimmest light.
Auto-off
Pick 15 minutes, 30 minutes, 1 hour or 2 hours under Turn off after. The countdown starts when you choose a time, or when you go fullscreen with a time chosen. At the end the light fades to black over 10 seconds, fullscreen ends and your phone or computer can sleep on its own setting. Want to wake up later? Set the alarm clock first.
Red for photos, parties and color effects
At full strength, Red, Scarlet and Crimson make a strong color wash behind a subject or across a room. A tablet in fullscreen works as a red backdrop for small products, and Download PNG saves any red as a background in five sizes.
Options explained
The eight swatches, Hex and the color picker set the red; Copy hex copies its code. Brightness runs from 5 to 100 %. Turn off after is off by default and remembers the last time you picked. Download PNG and Apply brightness to the image make the image, Share makes a link, and Settings holds Soft glow, tracking markers and Keep screen on.
How it works
Your browser draws the red as a CSS background, so it appears before any script has loaded. Brightness scales each channel, so #FF0000 at 50 % becomes #800000. Auto-off is one timer that releases the screen wake lock when it ends. Nothing is uploaded, and there’s no 10- or 24-hour video to stream.
Tips and limits (not a darkroom safelight)
- Darkroom paper makers specify tested safelights and a fog test (Ilford). A phone or monitor isn’t a safelight, so use a real one for printing.
- Red isn’t a color temperature. Even the warmest screen light, 2700 K (
#FFA757), is far brighter and more yellow. - We make no health or eye claims for any light, and this page doesn’t tint other apps; use the system settings above for that.
- On OLED screens a dim red lights few pixels, and a flat color wears them evenly.
- Plug in for an all-night session.
FAQ
Why do astronomers use red light at night?
To keep their night vision. NASA's Night Sky Network explains that eyes take about 30 minutes to adapt to the dark and that a bright light, a phone screen included, can undo that for a while; that is why stargazers use dim red lights. This page offers that kind of light, and it makes no health claims.
How dim can the red screen go?
Brightness stops at 5 %. Night red at 30 % shows #260000, and the same red at 5 % shows #060000, which is barely there in a dark room. For less light still, also turn your device brightness to its minimum; on iPhone, Reduce White Point dims the screen further.
How do I make my whole iPhone screen red?
Use Color Filters. Go to Settings → Accessibility → Display & Text Size → Color Filters, switch them on, choose Color Tint and move the hue fully to red with the intensity up. Add Color Filters to the Accessibility Shortcut and a triple-click of the side button turns the red on and off.
Why did my iPhone screen turn red?
Most likely Color Filters with Color Tint is switched on, perhaps through the triple-click Accessibility Shortcut. Turn it off at Settings → Accessibility → Display & Text Size → Color Filters, or triple-click again. If the red is this page, press ✕ or Esc to leave fullscreen.
Can I choose a darker or brighter red?
Yes. Red #FF0000 is the brightest. Dark red and Night red are darker, Tomato is softer and Crimson cooler. The Brightness slider dims any of them in 5 % steps, and Hex or the color picker accept any red you like, from #FF2400 to #3A0000.
Can I download a red screen background?
Yes, in five sizes from 1280×720 to 3840×2160, plus 1080×1920 for phones. Press Download PNG and the file is drawn on your device, named after its color, like red-screen-FF0000-1920x1080.png. Tick Apply brightness to the image to save the dimmed color instead.
Is a red screen safe for photo darkrooms?
No. Photographic paper makers say to use a tested safelight and to check it with a fog test, because the wrong light fogs paper. A phone or monitor isn't a safelight: nobody has tested its red light against your paper, and a screen can't be filtered like one. Use a real safelight in the darkroom.
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