663399 (rebeccapurple) — RGB, HSL, CMYK and Contrast

Q: What text colour should sit on 663399?

Black gives 2.50:1 and white gives 8.41:1, so white wins at 8.41:1. That clears the 4.5:1 AA threshold for normal text and the 7:1 AAA threshold as well.

Every value recomputed from the hex code · WCAG 2.1 contrast ratios

A purple at 40% lightness and 50% saturation, which puts it at 8.41:1 against white and 2.50:1 against black. The tables below give the notation conversions, the tints and shades that keep the hue intact, and the harmonies that pair with it.

663399

Notation conversions

Notation	Value
HEX	`663399`
RGB	rgb(102, 51, 153)
HSL	hsl(270, 50%, 40%)
CMYK	cmyk(33%, 67%, 0%, 40%)
Relative luminance	0.0749
Perceived brightness	30.5 / 100

R=102 G=51 B=153 · hue 270.0° · saturation 50.0% · lightness 40.0%

Contrast against pure white and pure black

Pair this colour with the two extremes to see which is the safer text partner. AA needs 4.5:1 for body text and 3:1 for large text; AAA raises that to 7:1 and 4.5:1.

Against	Hex	Ratio	AA text	AA large	AAA text
#FFFFFF	`white`	8.41:1	pass	pass	pass
#000000	`black`	2.50:1	fail	fail	fail

Tints and shades

Lightness moves in ten-point steps while hue and saturation stay fixed, which keeps the colour recognisable in a scale. The last column is the ratio against white text, useful for deciding where a scale stops working as a background.

Step	Hex	HSL	vs white text
shade -30	`#1a0d26`	hsl(270, 50%, 10%)	18.59:1
shade -20	`#331a4d`	hsl(270, 50%, 20%)	15.05:1
shade -10	`#4d2673`	hsl(270, 50%, 30%)	11.41:1
tint +10	`#8040bf`	hsl(270, 50%, 50%)	6.17:1
tint +20	`#9966cc`	hsl(270, 50%, 60%)	4.10:1
tint +30	`#b38cd9`	hsl(270, 50%, 70%)	2.74:1

Harmonies

Scheme	Hex
Complementary	`#669933`
Analogous −30	`#333399`
Analogous +30	`#993399`
Triadic −120	`#339966`
Triadic +120	`#996633`

Read back from the notation table, 663399 is rgb(102, 51, 153), which normalises to hue 270.0° at 50.0% saturation and 40.0% lightness. Its relative luminance of 0.0749 is what produces the two ratios above: 8.41:1 against white and 2.50:1 against black, a gap of 5.91. Position 45 of 69 in the colour library, it darkens to #1a0d26 thirty points lower on the lightness axis and lifts to #b38cd9 thirty higher, while the complementary rotation lands on #669933.

Nearby colours

2196F3 Blue 500 4169E1 royalblue 4B0082 indigo 673AB7 Deep Purple 500 9370DB mediumpurple 800080 purple

Frequently asked questions

What text colour should sit on 663399?
Black gives 2.50:1 and white gives 8.41:1, so white wins at 8.41:1. That clears the 4.5:1 AA threshold for normal text and the 7:1 AAA threshold as well.

Do the CMYK numbers match a print workflow?
They are the naive conversion from RGB, which assumes no ink limit, no colour profile and no black generation strategy. Real print work needs a profile-aware conversion; the values here are the ones the converter reports and are best used as a starting point for a designer rather than a press-ready separations file.

Convert any other colour, or test a pair against each other, in the ColrShift colour converter and contrast checker. The colour library groups every entry on this site by hue family.