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Tomblike Indigotin

#28399c
Notes

Tomblike Indigotin (#28399C) is a true blue 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 (231°, 59%, 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 amber. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#28399c
RGB
rgb(40, 57, 156)
HSL
hsl(231, 59%, 38%)
HWB
hwb(231 16% 39%)
OKLCH
oklch(39.8% 0.161 269.8)
HSV
hsv(231, 74%, 61%)
LAB
lab(28.84% 28.87 -55.83)
LCH
lch(28.84% 62.85 297.35)
CMYK
cmyk(74%, 63%, 0%, 39%)

Etymology

Tomblike
adjective

Greek tymbos, tomb — adjectival suffix -like. As a color modifier, tomblike implies the deep-and-funereal-and-sepulchral quality of Etruscan-and-Egyptian rock-cut royal-tomb interiors, particularly the Valley-of-the-Kings and Cerveteri-necropolis hand-carved chamber-painting walls. Sits at the deep-and-funereal end of the grid, parallel to sepulchral and crypted.

Indigotin
noun

The chemical name for the indigo molecule (C₁₆H₁₀N₂O₂) — extracted from Indigofera dye plants and chemically synthesized industrially since 1897 (BASF's process). Indigotin names the pure pigment distinct from the unpurified plant-dye indigo. The color refers to fresh indigotin-dyed cotton: a saturated, slightly cool deep blue.

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

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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.

#28399c
Original
#004a9f
Protanopia
#003f9a
Deuteranopia
#005365
Tritanopia
#3d3d3d
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
9.74:1
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
2.16:1

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