Color

#b31929

#b31929
hex#b31929
rgbrgb(179, 25, 41)
hslhsl(354, 75%, 40%)
oklchoklch(0.494 0.185 23.3)
Closest name: firebrick (#b22222)Relative luminance 0.1044

Colors that go with #b31929

Royal Blue, Steel Blue and Teal lead the list. Each partner is a real named colour with the reason it works — a wheel relationship, a neutral that carries it, or a pairing lifted from a palette or brand system that actually shipped — and every pair opens in the palette tool.

Tints & shades

Every swatch is its own page — click any to analyze it.

Harmonies

Complementary

Open in tool →

#19b3a3

#b31975 · #b35719

#29b319 · #1929b3

Split-complementary

Open in tool →

#19b357 · #1975b3

#75b319 · #19b3a3 · #5719b3

Contrast

#b31929 as textRatioAAAA largeAAAFix
Aaon white
6.8:1passpassfail
  • AAA: use #ae1928 as the text (7.07:1)
Aaon black
3.09:1failpassfail
  • AA: use #e0293b as the text (4.55:1)
  • AAA: use #eb707c as the text (7.14:1)
  • AA: or shift the background to #d4d4d4 (4.59:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #b31929 as the background.

Brands using this color

Palettes built around it

Fonts for this mood

#b31929 reads as warm, vivid, playful. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #b31929
live endpoint

Point any MCP client at the shared colors endpoint and your agent gets the same engine as this page — direct_palette, edit_direction, check_palette, check_contrast — read-only, no key. Every direction it proposes comes with a /colors/d/… link: open it, lock what you like, paste the link back, and the agent edits rather than re-rolls.

endpointhttps://mcp.brandsweets.com/colors/mcp
claude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
try this prompt

analyze #b31929 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/b31929-c49d9c-62cb8e-2d241f-f1e9ee?lock=0&style=vibrant

Want the agent to remember your picks and write them into a living brand? Create a free BrandSweets workspace.

Machine-readable: color.md