Color

#1b339d

#1b339d
hex#1b339d
rgbrgb(27, 51, 157)
hslhsl(229, 71%, 36%)
oklchoklch(0.382 0.173 267)
Closest name: Depths of Night (#2c319b)Relative luminance 0.0503

Colors that go with #1b339d

Charcoal, Steel Blue and 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.

Tints & shades

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

Harmonies

Complementary

Open in tool →

#9d851b

#1b749d · #441b9d

#9d1b33 · #339d1b

Split-complementary

Open in tool →

#9d441b · #749d1b

#9d1b74 · #9d851b · #1b9d44

Contrast

#1b339d as textRatioAAAA largeAAAFix
Aaon white
10.46:1passpasspassPasses AAA — no fix needed.
Aaon black
2.01:1failfailfail
  • AA: use #516be1 as the text (4.54:1)
  • AAA: use #7c90e9 as the text (7.02:1)
  • AA: or shift the background to #ababab (4.56:1)
  • AAA: or shift the background to #d4d4d4 (7.06:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #1b339d as the background.

Brands using this color

Fonts for this mood

#1b339d reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #1b339d
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 #1b339d and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/1b339d-9c9fc4-df7e4e-231f2d-e9eef1?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