Color

#b3000f

#b3000f
hex#b3000f
rgbrgb(179, 0, 15)
hslhsl(355, 100%, 35%)
oklchoklch(0.482 0.197 27.3)
Closest name: All Systems Red (#b30103)Relative luminance 0.0962

Colors that go with #b3000f

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 →

#00b3a4

#b30068 · #b34a00

#0fb300 · #000fb3

Split-complementary

Open in tool →

#00b34a · #0068b3

#68b300 · #00b3a4 · #4a00b3

Contrast

#b3000f as textRatioAAAA largeAAAFix
Aaon white
7.18:1passpasspassPasses AAA — no fix needed.
Aaon black
2.92:1failfailfail
  • AA: use #eb0014 as the text (4.54:1)
  • AAA: use #ff616e as the text (7.19:1)
  • AA: or shift the background to #cfcfcf (4.61:1)
  • AAA: or shift the background to #fcfcfc (7:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #b3000f as the background.

Brands using this color

Fonts for this mood

#b3000f reads as warm, vivid, playful. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #b3000f
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 #b3000f and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/b3000f-c49e9c-62cb8f-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