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True Thaw Cerulean

#3983ce
Notes

True Thaw Cerulean (#3983CE) 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 (210°, 60%, 52%) 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 orange. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#3983ce
RGB
rgb(57, 131, 206)
HSL
hsl(210, 60%, 52%)
HWB
hwb(210 22% 19%)
OKLCH
oklch(59.9% 0.136 251.4)
P3
color(display-p3 0.3014 0.5072 0.7852)
HSV
hsv(210, 72%, 81%)
LAB
lab(53.55% 2.19 -45.35)
LCH
lch(53.55% 45.40 272.76)
CMYK
cmyk(72%, 36%, 0%, 19%)

Etymology

True
adjective

Old English trēowe, faithful — used as a color modifier since the seventeenth century for hues that read as the canonical version of their family. True red, true blue: the saturation is full, the hue is neither shifted nor adulterated. Sits at the center of the bold and crisp buckets, marking the unequivocal middle of any chromatic family.

Thaw
modifier

Old English thawian, to-melt-or-soften. As a color modifier, thaw implies a spring-melt-and-softening-frost quality, the visual register of English-spring-and-Pennine-thaw hand-spring-melt-and-softening-frost English-spring-and-Pennine-thaw-and-Cumbria-Highland-thaw thaw-and-spring-melt-and-softening-frost surfaces under English-spring-and-Pennine-thaw-and-Cumbria-Highland-thaw Yorkshire-Dales-and-Lake-District-and-Cairngorm spring-melt-light. Sits at the modifier-and-weather end of the grid, parallel to slush and rain 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.

#3983ce
Original
#6188d1
Protanopia
#4b7acd
Deuteranopia
#00959f
Tritanopia
#797979
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).
AA Largeon White
3.95:1
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
5.31:1

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
##3983CE
Display P3
Display P3
color(display-p3 0.3014 0.5072 0.7852)
P3 has subtle headroomOKLCH chroma 0.136

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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