Color

#1d3dbf

#1d3dbf
hex#1d3dbf
rgbrgb(29, 61, 191)
hslhsl(228, 74%, 43%)
oklchoklch(0.434 0.205 266.2)
Closest name: Cobalt Blue (#0047ab)Relative luminance 0.0736

Colors that go with #1d3dbf

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 →

#bf9e1d

#1d8ebf · #4d1dbf

#bf1d3d · #3dbf1d

Split-complementary

Open in tool →

#bf4d1d · #8ebf1d

#bf1d8e · #bf9e1d · #1dbf4d

Contrast

#1d3dbf as textRatioAAAA largeAAAFix
Aaon white
8.49:1passpasspassPasses AAA — no fix needed.
Aaon black
2.47:1failfailfail
  • AA: use #4e6ce4 as the text (4.59:1)
  • AAA: use #7a91eb as the text (7.08:1)
  • AA: or shift the background to #bdbdbd (4.52:1)
  • AAA: or shift the background to #ebebeb (7.13:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #1d3dbf as the background.

Brands using this color

Fonts for this mood

#1d3dbf reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #1d3dbf
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 #1d3dbf and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/1d3dbf-9c9fc4-df7c4e-231f2d-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