Color

#515c7b

#515c7b
hex#515c7b
rgbrgb(81, 92, 123)
hslhsl(224, 21%, 40%)
oklchoklch(0.478 0.052 269.3)
Closest name: Deep Indigo (#4c567a)Relative luminance 0.1083

Colors that go with #515c7b

Charcoal, Sea Green and Steel Blue 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.

Real palettes that use #515c7b

Tints & shades

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

Harmonies

Complementary

Open in tool →

#7b7051

#51717b · #5b517b

#7b515c · #5c7b51

Split-complementary

Open in tool →

#7b5b51 · #717b51

#7b5171 · #7b7051 · #517b5b

Contrast

#515c7b as textRatioAAAA largeAAAFix
Aaon white
6.63:1passpassfail
  • AAA: use #4d5775 as the text (7.15:1)
Aaon black
3.17:1failpassfail
  • AA: use #68769c as the text (4.66:1)
  • AAA: use #8a95b2 as the text (7.02:1)
  • AA: or shift the background to #d6d6d6 (4.56:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #515c7b as the background.

Brands using this color

mcpConnect your agent — build around #515c7b
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 #515c7b and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/515c7b-9ca2c4-df724e-221f2d-e9eff1?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