Color

#1b308d

#1b308d
hex#1b308d
rgbrgb(27, 48, 141)
hslhsl(229, 68%, 33%)
oklchoklch(0.36 0.155 267.6)
Closest name: Deep Space Royal (#223382)Relative luminance 0.0427

Colors that go with #1b308d

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 →

#8d781b

#1b698d · #3f1b8d

#8d1b30 · #308d1b

Split-complementary

Open in tool →

#8d3f1b · #698d1b

#8d1b69 · #8d781b · #1b8d3f

Contrast

#1b308d as textRatioAAAA largeAAAFix
Aaon white
11.33:1passpasspassPasses AAA — no fix needed.
Aaon black
1.85:1failfailfail
  • AA: use #546dde as the text (4.62:1)
  • AAA: use #7e92e7 as the text (7.15:1)
  • AA: or shift the background to #a6a6a6 (4.65:1)
  • AAA: or shift the background to #cccccc (7.05:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #1b308d as the background.

Brands using this color

Fonts for this mood

#1b308d reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #1b308d
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 #1b308d and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/1b308d-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