Color

#1b38bb

#1b38bb
hex#1b38bb
rgbrgb(27, 56, 187)
hslhsl(229, 75%, 42%)
oklchoklch(0.421 0.206 266.4)
Closest name: Blue Hour (#0034ab)Relative luminance 0.0665

Colors that go with #1b38bb

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.

Tints & shades

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

Harmonies

Complementary

Open in tool →

#bb9e1b

#1b89bb · #4e1bbb

#bb1b38 · #38bb1b

Split-complementary

Open in tool →

#bb4e1b · #89bb1b

#bb1b89 · #bb9e1b · #1bbb4e

Contrast

#1b38bb as textRatioAAAA largeAAAFix
Aaon white
9.01:1passpasspassPasses AAA — no fix needed.
Aaon black
2.33:1failfailfail
  • AA: use #516ce6 as the text (4.64:1)
  • AAA: use #7e92ed as the text (7.22:1)
  • 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 #1b38bb as the background.

Brands using this color

Fonts for this mood

#1b38bb reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #1b38bb
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 #1b38bb and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/1b38bb-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