Color

#15515b

#15515b
hex#15515b
rgbrgb(21, 81, 91)
hslhsl(189, 63%, 22%)
oklchoklch(0.402 0.061 211)
Closest name: Raging Thunderstorm (#004f63)Relative luminance 0.068

Colors that go with #15515b

Steel Blue, Teal and Rust 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 →

#5b1f15

#155b43 · #152d5b

#5b1551 · #515b15

Split-complementary

Open in tool →

#5b152d · #5b4315

#43155b · #5b1f15 · #2d5b15

Contrast

#15515b as textRatioAAAA largeAAAFix
Aaon white
8.9:1passpasspassPasses AAA — no fix needed.
Aaon black
2.36:1failfailfail
  • AA: use #218191 as the text (4.61:1)
  • AAA: use #2aa5bb as the text (7.2:1)
  • AA: or shift the background to #bababa (4.59:1)
  • AAA: or shift the background to #e6e6e6 (7.13:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #15515b as the background.

Brands using this color

Fonts for this mood

#15515b reads as cool, vivid, dark. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #15515b
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 #15515b and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/15515b-a2b7be-df4e7e-1f252d-e9f1ee?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