Firebrick

Conversion

The same colour in each notation. OKLCH is the one to reach for when you intend to modify it, because its lightness axis is perceptually uniform and its three components are genuinely independent.

HEX

#B22222

RGB

rgb(178 34 34)

OKLCH

oklch(49.7% 0.180 26.8)

Contrast and accessibility

What this colour passes as text, and — where it fails — the nearest colour that would pass while holding the same hue.

APCA scores it Lc 81 as 16px regular text on white. That is below the threshold for body copy at that size, even where the WCAG ratio passes.

Using Firebrick

In OKLCH terms this is an orange at 50% lightness and 0.18 chroma. Lightness is what decides every verdict below, which is why a colour can be perfect as a fill and unusable as the text on top of it.

• Body text on white6.67:1 clears the 4.5:1 minimum.yes
• Body text on black3.14:1 is under the 4.5:1 minimum.no
• Large text or headingsLarge text needs only 3:1, and this reaches 6.67:1 against white.yes
• Borders, icons and controlsClears the 3:1 that WCAG 1.4.11 asks of anything needed to identify a control.yes
• A background for white textWhite on this colour is 6.67:1.yes

None of this makes a design accessible on its own. Contrast is one success criterion among many, and WCAG 1.4.1 separately requires that colour is never the only way information is conveyed — so if Firebrick is carrying meaning here, give it a label or an icon as well.

Closest named colours

Ranked by CIEDE2000 perceptual distance, not by hex proximity. Two hex codes can look almost identical and sit far apart numerically, and the reverse.

• BrownΔE 3.1
• Dark RedΔE 9.5
• CrimsonΔE 9.6
• MaroonΔE 11.3
• SiennaΔE 12.5

Tints and shades

The same hue at eleven lightness steps, spaced evenly in OKLCH so they look evenly spaced. This is the family you would build a design system from.

Colour harmonies

Hue rotations around Firebrick, computed in OKLCH so every colour in a set holds the same perceived lightness — which is what a harmony is supposed to mean and what the same rotation in HSL fails to deliver.

Colour vision

How Firebrick appears under each simulated deficiency, using the Machado model applied to linear RGB.