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Robust Lurk Brick

#ac3728
Notes

Robust Lurk Brick (#AC3728) 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 (7°, 62%, 42%) 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
#ac3728
RGB
rgb(172, 55, 40)
HSL
hsl(7, 62%, 42%)
HWB
hwb(7 16% 33%)
OKLCH
oklch(50.6% 0.155 30.5)
HSV
hsv(7, 77%, 67%)
LAB
lab(40.67% 46.88 35.54)
LCH
lch(40.67% 58.83 37.17)
CMYK
cmyk(0%, 68%, 77%, 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.

Lurk
modifier

Middle English lurken, to-lie-hidden. As a color modifier, lurk implies a hidden-and-watching-and-shadowed quality, the visual register of forest-edge-and-alley-mouth-lurk hand-hidden-and-watching-and-shadowed forest-edge-and-alley-mouth-and-bridge-undercroft lurked-and-hidden-and-watching-and-shadowed surfaces under forest-edge-and-alley-mouth-and-bridge-undercroft Gothic-novel-and-fairy-tale-and-noir half-light. Sits at the modifier-and-mood end of the grid, parallel to creep and prowl in usage.

Brick
noun

Fired clay, mineral red. The color refers to common building brick — iron-rich earthenware kilned to the specific dusky red-orange of a Victorian terrace, a Roman aqueduct, an adobe wall in New Mexico. Less saturated than ruby, warmer than burgundy, with a chalky cast that reads as architectural rather than decorative.

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.

#ac3728
Original
#585025
Protanopia
#766924
Deuteranopia
#bd1334
Tritanopia
#4f4f4f
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
6.30:1
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
3.33:1

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