Color

#3f495f

#3f495f
hex#3f495f
rgbrgb(63, 73, 95)
hslhsl(221, 20%, 31%)
oklchoklch(0.406 0.039 265.6)
Closest name: Bonne Nuit (#3a4866)Relative luminance 0.0665

Colors that go with #3f495f

Steel Blue, Blue and Blush Pink 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 →

#5f553f

#3f595f · #453f5f

#5f3f49 · #495f3f

Split-complementary

Open in tool →

#5f453f · #595f3f

#5f3f59 · #5f553f · #3f5f45

Contrast

#3f495f as textRatioAAAA largeAAAFix
Aaon white
9.01:1passpasspassPasses AAA — no fix needed.
Aaon black
2.33:1failfailfail
  • AA: use #667699 as the text (4.62:1)
  • AAA: use #8b97b1 as the text (7.16:1)
  • AA: or shift the background to #b8b8b8 (4.54:1)
  • AAA: or shift the background to #e3e3e3 (7.02:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #3f495f as the background.

Brands using this color

mcpConnect your agent — build around #3f495f
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 #3f495f and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3f495f-9ca4c4-df6b4e-211f2d-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