Inspect Crimson (#DC143C) in HEX, RGB, HSL, LCH and OKLCH, check its contrast, and copy the value you need.
Crimson
#DC143C
White text reads best on this background, at 4.99:1.
Crimson is one of the 148 CSS named colors, and resolves to #DC143C in every browser. In numbers that is rgb(220, 20, 60) and hsl(348, 83%, 47%). Perceptually it is a mid-toned, vivid color: OKLCH puts its lightness at 57% and its chroma at 0.222. It sits in the reds at 20 degrees of OKLCH hue, and reads as a warm color.
White text clears WCAG AA on a Crimson background at 4.99:1. At this chroma it is loud enough to be an accent or a call to action, but it will fight anything else vivid placed next to it.
The closest CSS named colors to Crimson, measured with CIEDE2000, are FireBrick (#B22222), IndianRed (#CD5C5C), Brown (#A52A2A). If Crimson is not quite right, those are the nearest keywords to try before reaching for a custom value.
HEX
#DC143C
RGB
rgb(220, 20, 60)
HSL
hsl(348, 83%, 47%)
HWB
hwb(348 8% 14%)
CMYK
cmyk(0%, 91%, 73%, 14%)
LAB
lab(47.88 71.28 35.48)
LCH
lch(47.88 79.62 26.46)
OKLCH
oklch(57.12% 0.2219 20.09)
WCAG asks for 4.5:1 between body text and its background. On #DC143C white text measures 4.99:1 and black text 4.21:1, so white clears it and black does not.
White text on Crimson
WCAG 2.2
4.99:1
APCA
Lc 77
Passes AA body text
Fails AAA body text
Passes AA large text
Black text on Crimson
WCAG 2.2
4.21:1
APCA
Lc 31
Fails AA body text
Fails AAA body text
Passes AA large text
Check Crimson against any other color in the contrast checker.
Crimson sits at 57% OKLCH lightness. Holding its hue and chroma and moving only that value carries it up to #FFF6F6 and down to #140001, which keeps the family recognizable instead of letting it drift toward gray the way a plain HSL ramp does.
#FA3E54
20% lighter
#FF7A7E
40% lighter
#FFA8A7
60% lighter
#FFD0CF
80% lighter
#FFF6F6
100% lighter
#B1002C
20% darker
#85001E
40% darker
#5C0012
60% darker
#360007
80% darker
#140001
100% darker
Build a full accessible scale from #DC143C in the shade generator.
Hues rotated around #DC143C in OKLCH, then pulled back into the sRGB gamut. Each swatch is labelled with the nearest CSS named color so you have a keyword to start from.
Crimson sits at 20 degrees. Rotating it a half turn lands on 200 degrees, the hue directly opposite. It is the strongest pairing you can make without changing lightness, and the one most likely to vibrate if you use both at full chroma.
The neighbors of Crimson at 350 and 50 degrees. They stay close enough to read as the same family, which is what you want for hover states, secondary surfaces and gradients.
20, 140 and 260 degrees divide the wheel into thirds. Balanced enough to carry a whole palette without one color dominating the other two.
Instead of the complement at 200 degrees, this pair flanks it at 170 and 230. You keep most of the contrast of a complementary pairing while losing the harshness.
Explore more combinations around Crimson on the color wheel.
The biggest shift is under protanopia, where #DC143C reads as #2A2F3D, 39.6 CIEDE2000 units away. If Crimson is the only thing marking a state or a series, roughly one viewer in twelve will miss it.
Protanopia
#2A2F3D
Deuteranopia
#544E38
Tritanopia
#FF0A21
Achromatopsia
#424141
The nearest CSS keywords to #DC143C, ranked by perceptual distance rather than by how close their hex digits happen to look.