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Cavernous Blueberry

#42378a
Notes

Cavernous Blueberry (#42378A) is a true blue with an earthy character. It leans grounded and natural, the kind of color that plays well with wood, clay, linen, and warm neutrals. Its HSL profile (248°, 43%, 38%) 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 yellow. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#42378a
RGB
rgb(66, 55, 138)
HSL
hsl(248, 43%, 38%)
HWB
hwb(248 22% 46%)
OKLCH
oklch(39.7% 0.133 284.6)
P3
color(display-p3 0.2518 0.2173 0.5221)
HSV
hsv(248, 60%, 54%)
LAB
lab(28.71% 28.22 -44.91)
LCH
lch(28.71% 53.04 302.14)
CMYK
cmyk(52%, 60%, 0%, 46%)

Etymology

Cavernous
adjective

An adjectival form of cavern, used principally for the deep darkness of large enclosed spaces. As a color modifier, cavernous implies the slightly cool deep blacks of a Lascaux-style cave or a basilica crypt — darkness with the optical complexity of a space larger than any single light source can fill. Sits in the deep-and-spatial end of the grid.

Blueberry
noun

The genus Vaccinium — North American native berry shrubs cultivated since the early twentieth century. The fruit's deep blue-purple skin is colored by anthocyanin and the protective bloom of waxy yeast cells. The color refers to a fresh wild blueberry: a saturated, slightly cool deep blue-violet with the powdery finish of waxy fruit surface.

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.

#42378a
Original
#00468d
Protanopia
#004188
Deuteranopia
#274a5b
Tritanopia
#3f3f3f
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).
AAAon White
9.79:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
Failon Black
2.15:1

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
##42378A
Display P3
Display P3
color(display-p3 0.2518 0.2173 0.5221)
P3 has subtle headroomOKLCH chroma 0.133

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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