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Commanding Altair Cerulean

#047bc5
Notes

Commanding Altair Cerulean (#047BC5) is a true azure with a cool character. It leans cool, sitting on the blue, green, and violet side of the wheel. Quiet and dependable, a fit for product UI and data visualization. Its HSL profile (203°, 96%, 39%) places it in the highly saturated band at a mid lightness. Best used in small doses, like logos, CTAs, focus rings, or highlight text, where its saturation becomes a feature rather than noise. For a confident two-color system, pair it with its complementary orange. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#047bc5
RGB
rgb(4, 123, 197)
HSL
hsl(203, 96%, 39%)
HWB
hwb(203 2% 23%)
OKLCH
oklch(56.5% 0.145 246.2)
P3
color(display-p3 0.2096 0.4749 0.7501)
HSV
hsv(203, 98%, 77%)
LAB
lab(49.76% -0.61 -46.30)
LCH
lch(49.76% 46.31 269.25)
CMYK
cmyk(98%, 38%, 0%, 23%)

Etymology

Commanding
adjective

Latin commendāre, to entrust / order — present-participle of command. As a color modifier, commanding implies a saturated-and-authoritative quality where the hue claims visual leadership of its surrounding palette. Sits at the bold-and-authoritative end of the grid, parallel to authoritative and imperial in usage.

Altair
modifier

Arabic al-nasr-al-tā'ir, the-flying-eagle. As a color modifier, altair implies a fast-spinning-and-summer-triangle quality, the visual register of Aquila-Eagle-and-Summer-Triangle-Altair hand-fast-spinning-and-summer-triangle Aquila-Eagle-and-Summer-Triangle-and-Bortle-1-sky altair-and-fast-spinning-and-summer-triangle surfaces under Aquila-Eagle-and-Summer-Triangle-and-Bortle-1-sky July-and-August-summer-vista white-stellar-light. Sits at the modifier-and-cosmic end of the grid, parallel to vega and deneb in usage.

Cerulean
noun

From the Latin caeruleum, originally referring to dark blue paint pigment of the Roman world, then via French céruléen into English. As a modern art-supply name, cerulean blue is the cobalt-tin oxide pigment introduced in 1805. The color refers to a clean, slightly green-shifted blue with the matte finish of mineral pigment in linseed oil: lighter than cobalt, deeper than aqua, with the painter's weight of a word for sky.

Closest matches

The nearest named color in three reference sources, ranked by perceptual distance (ΔE76 in CIELAB). ΔE < 1 is imperceptible to most viewers; ΔE > 10 is clearly different. When two sources point to the same hex they’re merged into one tile; click any to open that color’s page.

Variations

Click any swatch to explore

Harmonies

Accessibility

Color-vision simulation

How this color appears to viewers with the four major color-vision-deficiency types. Computed via the Machado (2009) physiologically-based model. If a tile matches the original, the color reads the same to that viewer.

#047bc5
Original
#577fc8
Protanopia
#3b6fc4
Deuteranopia
#008d96
Tritanopia
#676767
Achromatopsia
WCAG contrast

The color used as foreground text against pure white and pure black, with the contrast ratio and WCAG 2.1 grade. Aim for AA (4.5:1) for body text and AA Large (3:1) for 18 pt+ headlines; AAA (7:1) is the gold standard for long-form reading surfaces.

The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAon White
4.52:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAon Black
4.64:1

Wide gamut

Display P3 representation

The CSS Color 4 wide-gamut form of this color. Both swatches render the same color on every display — the P3 form only diverges from sRGB when a designer pushes channels outside sRGB's reach.

sRGB hex
sRGB hex
##047BC5
Display P3
Display P3
color(display-p3 0.2096 0.4749 0.7501)
P3 has subtle headroomOKLCH chroma 0.145

Moderately saturated colors gain a small bump in P3 — the difference is usually visible side-by-side on wide-gamut hardware but won't change the character of the color.

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