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Smoldering Surkh

#ad140a
Notes

Smoldering Surkh (#AD140A) is a true red with a jewel character. It carries the deep, saturated richness of a gemstone. Authoritative and slightly formal, it works well for type and heavy UI elements. Its HSL profile (4°, 89%, 36%) places it in the highly saturated band at a mid lightness. Best used in small doses, like logos, CTAs, focus rings, or highlight text, where its saturation becomes a feature rather than noise. 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
#ad140a
RGB
rgb(173, 20, 10)
HSL
hsl(4, 89%, 36%)
HWB
hwb(4 4% 32%)
OKLCH
oklch(47.7% 0.185 29.6)
P3
color(display-p3 0.6221 0.1544 0.1025)
HSV
hsv(4, 94%, 68%)
LAB
lab(36.76% 57.25 46.71)
LCH
lch(36.76% 73.89 39.21)
CMYK
cmyk(0%, 88%, 94%, 32%)

Etymology

Smoldering
adjective

The progressive participle of smolder, to burn slowly without flame. Used as a color word since the late nineteenth century for the deep reds and oranges of barely-flame coal — the warm saturated darks where the heat is internal rather than emitted. Sits in the bold-and-warm corner, slightly less luminous than burning and slightly less calm than rich.

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.

#ad140a
Original
#4b4104
Protanopia
#6f6200
Deuteranopia
#bf0015
Tritanopia
#343434
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
7.29:1
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
2.88:1

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
##AD140A
Display P3
Display P3
color(display-p3 0.6221 0.1544 0.1025)
P3 has visible headroomOKLCH chroma 0.185

This color is chromatic enough that authoring it as P3 native (instead of clamping to sRGB) gives a perceptibly more saturated render on wide-gamut displays — modern Macs, iPhones, iPads, and most recent OLED laptops.

Related Colors

Canvas