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Robust Surkh

#d53528
Notes

Robust Surkh (#D53528) is a true red with a vibrant character. It holds its own as a focal accent, carrying visual weight without tipping into neon territory. Its HSL profile (5°, 68%, 50%) 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
#d53528
RGB
rgb(213, 53, 40)
HSL
hsl(5, 68%, 50%)
HWB
hwb(5 16% 16%)
OKLCH
oklch(57.6% 0.198 29.3)
HSV
hsv(5, 81%, 84%)
LAB
lab(48.07% 60.83 45.53)
LCH
lch(48.07% 75.98 36.81)
CMYK
cmyk(0%, 75%, 81%, 16%)

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.

Surkh
noun

The Persian word for red in its most saturated, formal sense — used in Iranian poetry and miniature painting for the ribbons of court banners, the robes of warriors, and the high-saturation reds of Safavid tile. The color refers to a surkh-dyed Persian carpet: a saturated, slightly cool deep red with the matte finish of plant-dye-on-wool. Deeper than crimson, warmer than burgundy.

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.

#d53528
Original
#675c24
Protanopia
#8e7f20
Deuteranopia
#eb0034
Tritanopia
#565656
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
4.81:1
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
4.37:1

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