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Combustive Bistre

#efc53b
Notes

Combustive Bistre (#EFC53B) is a true amber with a neon character. It sits at the high-saturation edge of its family. Use it sparingly, as signage, accent, or highlight against darker surfaces. Its HSL profile (46°, 85%, 58%) 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 blue. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#efc53b
RGB
rgb(239, 197, 59)
HSL
hsl(46, 85%, 58%)
HWB
hwb(46 23% 6%)
OKLCH
oklch(83.8% 0.154 91.1)
HSV
hsv(46, 75%, 94%)
LAB
lab(81.07% 1.64 70.22)
LCH
lch(81.07% 70.23 88.67)
CMYK
cmyk(0%, 18%, 75%, 6%)

Etymology

Combustive
adjective

Latin combūstus, burnt — adjectival suffix -ive, derived from com-burere (to burn-up). As a color modifier, combustive implies a saturated-and-burning-active quality, the bright color of blast-furnace-and-foundry combustion-chamber emission. Sits at the bright-and-warm end of the grid, parallel to fiery and blazing in usage.

Bistre
noun

A traditional French painter's pigment made from soot suspended in gum arabic — used for sepia-style washes in Old Master drawings. The color refers to a bistre wash on Rembrandt-period drawing paper: a soft, slightly muted warm brown with the translucent finish of soot-and-binder. Cooler than walnut, drier than caramel.

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.

#efc53b
Original
#dbc222
Protanopia
#e6ce43
Deuteranopia
#ffb4aa
Tritanopia
#c4c4c4
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).
Failon White
1.65:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAAon Black
12.72:1

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