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Effective Dux Topaz

#19c5b7
Notes

Effective Dux Topaz (#19C5B7) is a true cyan with a vibrant character. It holds its own as a focal accent, carrying visual weight without tipping into neon territory. Its HSL profile (175°, 77%, 44%) 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 red. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#19c5b7
RGB
rgb(25, 197, 183)
HSL
hsl(175, 77%, 44%)
HWB
hwb(175 10% 23%)
OKLCH
oklch(74.2% 0.127 185.7)
HSV
hsv(175, 87%, 77%)
LAB
lab(71.93% -42.75 -4.40)
LCH
lch(71.93% 42.97 185.88)
CMYK
cmyk(87%, 0%, 7%, 23%)

Etymology

Effective
adjective

Latin effectīvus, productive — adjectival suffix -ive. As a color modifier, effective implies a clear-and-purpose-achieving quality where the hue carries the visual register of successful-task-completion design-element. Sits at the crisp-and-functional end of the grid, parallel to practical and useful in usage.

Dux
modifier

Latin dux, leader-or-general. As a color modifier, dux implies a Latin-leader-and-Roman-general-and-Doge quality, the visual register of Roman-dux-and-Venetian-Doge hand-Latin-leader-and-Roman-general-and-Doge Roman-dux-and-Venetian-Doge-and-Renaissance-condottiere dux-and-Latin-leader surfaces under Roman-dux-and-Venetian-Doge-and-Renaissance-condottiere Republican-Rome-and-Venetian-Doge's-Palace leader-and-general-light. Sits at the modifier-and-Latin end of the grid, parallel to pater and virtus in usage.

Topaz
noun

A fluorine aluminum silicate gem, hardness 8 on the Mohs scale, mined for centuries in Ouro Preto, Brazil. Imperial topaz is the prized variety: a warm, slightly pink-shifted gold-orange with the high refractive index of a quality cut stone. Cooler than amber, brighter than honey, with the gem's signature internal fire when held to light. Named for the island of Topazos in the Red Sea, though that source produced peridot instead.

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.

#19c5b7
Original
#bab9b7
Protanopia
#a5aab9
Deuteranopia
#00cac0
Tritanopia
#9f9f9f
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
2.16:1
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
9.71:1

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