4B0082 (indigo) — RGB, HSL, CMYK and Contrast

Q: What text colour should sit on 4B0082?

Black gives 1.62:1 and white gives 12.95:1, so white wins at 12.95:1. 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 25% lightness and 100% saturation, which puts it at 12.95:1 against white and 1.62:1 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.

4B0082

Notation conversions

Notation	Value
HEX	`4B0082`
RGB	rgb(75, 0, 130)
HSL	hsl(275, 100%, 25%)
CMYK	cmyk(42%, 100%, 0%, 49%)
Relative luminance	0.0311
Perceived brightness	14.6 / 100

R=75 G=0 B=130 · hue 274.6° · saturation 100.0% · lightness 25.5%

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`	12.95:1	pass	pass	pass
#000000	`black`	1.62:1	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	`#000000`	hsl(275, 100%, 0%)	21.00:1
shade -20	`#10001c`	hsl(275, 100%, 5%)	20.22:1
shade -10	`#2e004f`	hsl(275, 100%, 15%)	17.09:1
tint +10	`#6800b5`	hsl(275, 100%, 35%)	9.31:1
tint +20	`#8600e8`	hsl(275, 100%, 45%)	6.61:1
tint +30	`#9f1cff`	hsl(275, 100%, 55%)	5.14:1

Harmonies

Scheme	Hex
Complementary	`#378200`
Analogous −30	`#0a0082`
Analogous +30	`#820078`
Triadic −120	`#00824b`
Triadic +120	`#824b00`

Measured rather than eyeballed: hue 274.6°, saturation 100.0%, lightness 25.5%, relative luminance 0.0311 — four decimals is the precision the WCAG formula actually needs — and perceived brightness 14.6 out of 100. Entry 44 of 69 in this library, it scores 12.95:1 on white and 1.62:1 on black, a 11.33 spread. The complementary #378200 sits 180° away on the wheel, and the scale brackets it with #000000 below and #9f1cff above.

Nearby colours

708090 slategray 2196F3 Blue 500 4169E1 royalblue 663399 rebeccapurple 673AB7 Deep Purple 500 9370DB mediumpurple

Frequently asked questions

What text colour should sit on 4B0082?
Black gives 1.62:1 and white gives 12.95:1, so white wins at 12.95:1. 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.