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Solid Procyon Royal

#3664c9
Notes

Solid Procyon Royal (#3664C9) 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 (221°, 58%, 50%) places it in the balanced band at a mid lightness. It works across type, buttons, and borders, saturated enough to feel deliberate but balanced enough to not fight the rest of the palette. For a confident two-color system, pair it with its complementary amber. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#3664c9
RGB
rgb(54, 100, 201)
HSL
hsl(221, 58%, 50%)
HWB
hwb(221 21% 21%)
OKLCH
oklch(52.7% 0.165 263.4)
P3
color(display-p3 0.2552 0.3877 0.7622)
HSV
hsv(221, 73%, 79%)
LAB
lab(44.40% 19.26 -57.15)
LCH
lch(44.40% 60.31 288.62)
CMYK
cmyk(73%, 50%, 0%, 21%)

Etymology

Solid
adjective

Latin solidus, firm, dense — used as a color modifier since the seventeenth century for hues that read as continuous and unbroken: a solid blue is one with no variation across the surface. Implies high saturation combined with optical density. Sits in the bold-bucket alongside strong and robust, slightly more focused on uniformity.

Procyon
modifier

Greek προκύων, before-the-dog. As a color modifier, procyon implies a Canis-Minor-and-bright-foretaste-of-Sirius quality, the visual register of Canis-Minor-Procyon-and-Winter-Triangle hand-Canis-Minor-and-bright-foretaste-of-Sirius Canis-Minor-Procyon-and-Winter-Triangle-and-Bortle-1-sky procyon-and-Canis-Minor-and-bright-foretaste surfaces under Canis-Minor-Procyon-and-Winter-Triangle-and-Bortle-1-sky January-and-February-winter-zenith winter-stellar-light. Sits at the modifier-and-cosmic end of the grid, parallel to rigel and altair in usage.

Royal
noun

The blue of European royal court dress and regalia from the late seventeenth century forward — the color of British peers' robes, French royal sashes, the lining of the crown-jewel cases. The color refers to a saturated, slightly violet-shifted blue with the matte finish of velvet or melton wool dyed to maximum intensity: deeper than cornflower, warmer than ultramarine, with the heraldic weight of a color reserved for monarchs and the official Crown.

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.

#3664c9
Original
#2770cd
Protanopia
#0063c7
Deuteranopia
#007c8d
Tritanopia
#626262
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
5.49:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AA Largeon Black
3.82:1

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
##3664C9
Display P3
Display P3
color(display-p3 0.2552 0.3877 0.7622)
P3 has subtle headroomOKLCH chroma 0.165

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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