Cobalt Screen
A full-screen solid cobalt color (#0047AB). Fill your whole display, or download the cobalt screen as an image in 480p, 720p, 1080p, 1440p, 4K or any size you type in.
Advanced — print resolution (DPI)
What is a cobalt screen?
A cobalt screen is simply a web page filled edge to edge with one solid color — Cobalt, hex #0047AB, or rgb(0, 71, 171). It is a dark, cool color: in HSL it sits at 215° hue, 100% saturation and 34% lightness, and its relative luminance is 7.4%. The closest standard CSS color is Dark Slate Blue (#483D8B).
Cobalt screen at a glance
How a full-screen cobalt (#0047AB) behaves as a light, a test pattern and a background — measured from the color itself.
| Brightness | 7% of a white screen | A dim glow — easy on the eyes in a dark room. |
|---|---|---|
| Blue light | high (87% of its light) | More blue than a white screen — better for daytime than late at night. |
| Night use | Better for daytime | For a night light, turn the brightness down or choose a warmer screen such as red or orange. |
| Text on it | White text · 8.4:1 | Excellent contrast for captions or signs (WCAG AAA). |
| Display test | red switched off | A stuck-on red sub-pixel shows as a bright speck. |
What people use a cobalt screen for
As a saturated color, cobalt makes a bold backdrop for product photos, thumbnails and streams, and a strong mood light for a desk or party.
Blue screens are the standard for bias lighting — a dim blue or blue-white glow placed behind a monitor or TV lowers the perceived contrast of the room and eases eye strain during long sessions. Blue is also the reference for checking the blue sub-pixels of a panel, a favourite for "blue screen" jokes, and a moody backdrop for photography and streams.
As a test pattern, a dark cobalt field is best for spotting backlight bleed and IPS glow on an LCD, or stuck "always-on" pixels on an OLED.
#0047AB) — this is also the preview image shown when you share the page.How to use the cobalt screen
The color is already set to Cobalt (#0047AB). Tap Open full screen, or the preview, to fill your whole display with cobalt; press Esc or tap again to exit. To keep a copy, pick a size — 1920 × 1080 for a desktop wallpaper, 1080 × 1920 for a phone or 3840 × 2160 for a 4K TV — and tap Download PNG or JPG. The file is created in your browser and saved as cobalt-screen-1920x1080.png, with no watermark. A flat cobalt image compresses to a few kilobytes even at 4K.
Every resolution, aspect ratio and device tip (phones, TVs, projectors, second monitors) is in the full color screen guide.
Cobalt screen color codes
The full-screen color and every download use exactly these values. Tap any row to copy it.
Contrast against white text 8.44:1 · against black text 2.49:1. See the full Cobalt color page for harmonies, shades and tints, or open it in the color picker.
Colors that go with a cobalt screen
Using two screens side by side, a split display or a cobalt wallpaper with accents? These named colors sit in harmony with Cobalt on the color wheel:
Build a full scheme from cobalt in the color matcher or the palette generator, or blend it into another color with the gradient creator for a gradient wallpaper.
Popular color screens
The colors people reach for most often as a full-screen background or light:
Colors similar to Cobalt
More blue screens
Cobalt screen — FAQ
What is the hex code for a cobalt screen?
A cobalt screen uses the color Cobalt, hex #0047AB — rgb(0, 71, 171). The full-screen view and every download use exactly that value. The nearest standard CSS name is Dark Slate Blue (#483D8B).
How do I make my whole screen cobalt?
Open this page and tap Open full screen (or tap the preview). Your browser fills the entire display with cobalt and hides its own toolbars; press Esc or tap the screen to come back. To keep it, download it in 1080p, 4K or any size as a free PNG or JPG — no sign-up or watermark.
How bright is a cobalt screen?
A cobalt screen gives off about 7% of the light of a white screen at the same brightness setting, a comfortable level for ambient light. About 87% of its light is blue (a white screen is 33%), which counts as high blue light.
What color text is easiest to read on a cobalt screen?
White text, with a contrast ratio of 8.4:1, which passes the WCAG guideline for normal text. Check any other pairing in the contrast checker.
Does a cobalt screen save battery?
On phones and laptops with an OLED or AMOLED display, yes — dark pixels use very little power and true black uses none, so a cobalt screen draws less than a bright one. On a normal LCD the backlight stays on regardless, so the saving is small.