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Robust Madder

#ac3931
Notes

Robust Madder (#AC3931) is a true red with a warm character. It leans warm, pulling light toward red, orange, and yellow. Naturally inviting, it suits editorial and hospitality contexts. Its HSL profile (4°, 56%, 43%) 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 cyan. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#ac3931
RGB
rgb(172, 57, 49)
HSL
hsl(4, 56%, 43%)
HWB
hwb(4 19% 33%)
OKLCH
oklch(51.0% 0.152 27.7)
HSV
hsv(4, 72%, 67%)
LAB
lab(41.09% 46.44 30.84)
LCH
lch(41.09% 55.74 33.58)
CMYK
cmyk(0%, 67%, 72%, 33%)

Etymology

Robust
adjective

From the Latin robustus, of oak — implying strength combined with substance. As a color modifier, robust describes saturation combined with body: a robust burgundy, a robust olive. Sits in the bold-and-warm corner alongside strong and solid, with the slightly textural implication of a color that has substance behind the pigment.

Madder
noun

Rubia tinctorum, the dyer's madder — the root pigment that fed European red textile production from antiquity until synthetic alizarin replaced it in 1869. Less brilliant than kermes, more lightfast than safflower, madder-dyed wool was the workhorse red of Persian carpets, British redcoats, and Turkish kilim. The color carries that history: a warm, slightly orange red with the matte finish of cloth rather than glaze.

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.

#ac3931
Original
#59512f
Protanopia
#766a2d
Deuteranopia
#bd1a38
Tritanopia
#515151
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
6.21:1
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
3.38:1

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