Color

#1f4bbd

#1f4bbd
hex#1f4bbd
rgbrgb(31, 75, 189)
hslhsl(223, 72%, 43%)
oklchoklch(0.459 0.186 264.2)
Closest name: Cobalt Blue (#0047ab)Relative luminance 0.09

Colors that go with #1f4bbd

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 →

#bd901f

#1f9abd · #411fbd

#bd1f4b · #4bbd1f

Split-complementary

Open in tool →

#bd411f · #9abd1f

#bd1f9a · #bd901f · #1fbd41

Contrast

#1f4bbd as textRatioAAAA largeAAAFix
Aaon white
7.5:1passpasspassPasses AAA — no fix needed.
Aaon black
2.8:1failfailfail
  • AA: use #426fe0 as the text (4.58:1)
  • AAA: use #7394e8 as the text (7.13:1)
  • AA: or shift the background to #c9c9c9 (4.53:1)
  • AAA: or shift the background to #f7f7f7 (7:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #1f4bbd as the background.

Brands using this color

Fonts for this mood

#1f4bbd reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #1f4bbd
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 #1f4bbd and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/1f4bbd-9ca3c4-df704e-211f2d-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