Newsprint
Open in tool →Ink-black on warm paper with a single red — the broadsheet hierarchy that lets typography lead.
Color
#b51203
#b51203
hex
#b51203rgb
rgb(181, 18, 3)hsl
hsl(5, 97%, 36%)oklch
oklch(0.491 0.194 30.2)Closest name: Bullseye (#b9030a)Relative luminance 0.1026
Colors that go with #b51203
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.
Royal Blue #4169e1
triadicshippedRoyal Blue completes a triad with #b51203 — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash.
Steel Blue #4682b4
split-complementshippedSteel Blue is a split-complement of #b51203: nearly opposite, so it still pops against it, without the vibrating edge of a true complement.
Teal #008080
complementaryshippedTeal sits directly opposite #b51203 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Amber #ffbf00
shippedAmber is paired with #b51203 in 5 real palettes, including Maple and Ember, as the accent.
Blue #0000ff
shipped4 real palettes, including Tim Hortons's brand system and Dunkin''s brand system put Blue beside #b51203, as the accent.
Cobalt Blue #0047ab
shippedDesigners have shipped Cobalt Blue with #b51203: 4 real palettes, including MLB's brand system and Behance's brand system, as the accent.
Dark Olive Green #556b2f
shippedDark Olive Green shows up next to #b51203 in 5 real palettes, including Olive Grove and Cider, as the lead colour.
Charcoal #36454f
neutralshippedCharcoal is the body-text near-black for #b51203: its slight blue cast keeps type crisp beside a warm colour where pure #000 looks heavy.
Real palettes that use #b51203
Tints & shades
Harmonies
Contrast
| #b51203 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 6.88:1 | pass | pass | fail |
|
Aaon black | 3.05:1 | fail | pass | fail |
Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #b51203 as the background.
Brands using this color
Palettes built around it
Fonts for this mood
#b51203 reads as warm, vivid, playful. The font library is tagged with the same vocabulary:
mcpConnect your agent — build around #b51203
live endpointPoint 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.
endpoint
https://mcp.brandsweets.com/colors/mcpclaude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
try this prompt
›analyze #b51203 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
tool url
/palettes/new/b51203-c4a49c-62cba1-2d261f-f1e9ec?lock=0&style=vibrantWant the agent to remember your picks and write them into a living brand? Create a free BrandSweets workspace.
Machine-readable: color.md