Color

#331d9f

#331d9f
hex#331d9f
rgbrgb(51, 29, 159)
hslhsl(250, 69%, 37%)
oklchoklch(0.366 0.192 278.8)
Closest name: Depths of Night (#2c319b)Relative luminance 0.0409

Colors that go with #331d9f

Blue, Crimson and Denim 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 →

#8a9f1d

#1d499f · #741d9f

#9f331d · #1d9f33

Split-complementary

Open in tool →

#9f741d · #499f1d

#9f1d49 · #8a9f1d · #1d9f74

Contrast

#331d9f as textRatioAAAA largeAAAFix
Aaon white
11.56:1passpasspassPasses AAA — no fix needed.
Aaon black
1.82:1failfailfail
  • AA: use #7560e2 as the text (4.53:1)
  • AAA: use #9a8bea as the text (7.26:1)
  • AA: or shift the background to #a3a3a3 (4.58:1)
  • AAA: or shift the background to #cccccc (7.2:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #331d9f as the background.

Brands using this color

No public brand in the corpus uses this exact color yet. Extract a brand to add one.

Fonts for this mood

#331d9f reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #331d9f
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 #331d9f and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/331d9f-a79cc4-dfb14e-281f2d-e9ecf1?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