Cerulean#00C9FF, a cool brilliant turquoise
Cerulean in RGB, HSL, OKLCH & more
Ready to ship: every line pastes straight into your codebase, and the whole file copies at once.
ART is Rhapsody's perceptual model. How ART works
Why is it called Cerulean?
Cerulean's meaning, origin, and pronunciation, with sources.
Anchor: A39 · one of the 72 anchor hues of ART
Origin: Latin (caeruleus), perhaps, at bottom, "little sky"
Meaning: Blue. Roman caeruleus covered sky, sea, and occasionally leaves
suh-ROO-lee-un · /səˈruːliən/
Latin caeruleus, "blue" → English ceruleous in the 1570s → cerulean by the 1660s. The artist's pigment "cerulean blue" arrives much later, in 1885.
The Latin word may itself be a worn-down form of *caelulum, "little sky," from caelum, "sky." If that leading theory is right, and it is a theory rather than a certainty, then cerulean literally means "little sky."
Its best secret is older than any of that. The Romans used caeruleum as their name for Egyptian blue, the manufactured pigment whose Egyptian story is told at Irtyu, ten anchors away. One pigment, two anchors, two thousand years apart: the first blue humanity ever made, still traveling under a Roman alias.
Roman writers applied caeruleus to sky, sea, and sometimes foliage. It was never the tidy pastel we have made of it.
etymonline s.v. cerulean ("perhaps from a dissimilation of caelulum"); Wiktionary s.v. cerulean; Kelsey Museum (caeruleum = Egyptian blue). Etymological dictionaries + scholarly sources. Audio: EncycloPetey, CC BY-SA 3.0.
Shades of Cerulean, lighter and darker
For hover states, washed backgrounds, and dark surfaces that still read as #00C9FF. 13 steps, spaced evenly by eye, with the color itself sitting at its natural depth, cerulean-400.
Tints (light surfaces; dark text passes on every one)
Midtones (the color at full strength, for brand & accent work)
Shades (dark surfaces; light text passes on every one)
Most tools mix. Rhapsody measures.
Paste any color. The whole system comes back, contrast-checked before you see it.
The window on the right was generated from #00C9FF, like this whole page.
Is Cerulean accessible? Contrast with white & black
Strong contrast makes your work readable by everyone, and meets the WCAG standard accessibility law points at. AA is the floor; AAA is the tier worth aiming for in body text. Black text on #00C9FF clears WCAG AAA. Every strip below is one surface, and the marks are the steps that reach AAA on it.
Rows are text, columns are background · 68 of 210 pairings reach WCAG 2.2 AAA, shown here.
Ship the audit, not screenshots.
Run #00C9FF against the colors you actually ship, every pairing and any target, and export it: exact ratios, the AA tier, APCA, in one file.
The audit on the right was calibrated from #00C9FF, like this whole page.
Cerulean in CMYK: one value for files, one per press
This color shifts further than a press run can hold, so expect a visible difference. The pairs below show where each standard lands.
In CMYK, #00C9FF is . That is the value design tools and file formats use when no press is involved.
On press (what each standard prints)
shifts ΔE00 3.2, 1.3× the 2.5 a run varies by
shifts ΔE00 3.7, 1.5× the 2.5 a run varies by
shifts ΔE00 3.1, 1.2× the 2.5 a run varies by
shifts ΔE00 3.2, 1.3× the 2.5 a run varies by
shifts ΔE00 2.5, 1.0× the 2.5 a run varies by
Press values computed through the ICC characterization data each standard proofs against. Each CMYK above is the closest that standard can get.
No surprises at the printer.
Run any color through the major press standards: FOGRA51, GRACoL, Japan Color, FOGRA39. It's coming soon. Create a free account and you'll get a note the moment it's live.
The strip shows this page's tints and shades on screen, then through a standard GRACoL 2013 conversion.
Colors similar to Cerulean
Blue. Roman caeruleus covered sky, sea, and occasionally leaves
Here are other colors similar to Cerulean along with accessible text pairings and whether or not they're print-safe. Explore The Turquoises
| Bright Sky Blue | Bright Sky Blue | #02CCFE | black text · AAA | ✕ shifts on press |
| Peacock | Peacock | #00D4FF | black text · AAA | ✕ shifts on press |
| Neon Blue | Neon Blue | #04D9FF | black text · AAA | ✕ shifts on press |
| Aqua Blue | Aqua Blue | #02D8E9 | black text · AAA | ✕ shifts on press |
| Scooter | Scooter | #2EBFD4 | black text · AAA | ! within tolerance |
| Cielo | Cielo | #00DFFF | black text · AAA | ✕ shifts on press |
| Shakespeare | Shakespeare | #4EABD1 | black text · AAA | ✓ prints exactly |
| Anqas | Anqas | #00EAFF | black text · AAA | ✕ shifts on press |
| Turquoise Blue | Turquoise Blue | #06B1C4 | black text · AAA | ✓ prints exactly |
| Robin'S Egg | Robin'S Egg | #6DEDFD | black text · AAA | ✕ shifts on press |
| Kyanos | Kyanos | #00F4FF | black text · AAA | ✕ shifts on press |
| Bright Light Blue | Bright Light Blue | #26F7FD | black text · AAA | ✕ shifts on press |
| Pacific Blue | Pacific Blue | #009DC4 | black text · AA | ✓ prints exactly |
| Eastern Blue | Eastern Blue | #1E9AB0 | black text · AA | ✓ prints exactly |
| Bondi Blue | Bondi Blue | #0095B6 | black text · AA | ✓ prints exactly |
| Boston Blue | Boston Blue | #3B91B4 | black text · AA | ✓ prints exactly |
Colors that go with Cerulean
The complementary color, straight across the wheel, is a warm bold red #CB4954. Rhapsody's pick is the split complement, just to one side of it, a livelier pair.
The accent is for the moments that need attention, the harmony for the ones that need calm; the neutral carries the text and surfaces in between.
Take Cerulean with you
The work on this page doesn't stay here. Save a card and the color arrives in your file, your deck or your board already decided.
Your system is already built.
Rhapsody built it before you even asked: the scale, the neutrals, the utilities, every pairing calibrated.
This page's whole theme is built from one color. Palette does the same for yours: every step calibrated, every pairing checked, press included.
Every color on this page was calibrated, not mixed.
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