Color

#3904b4

#3904b4
hex#3904b4
rgbrgb(57, 4, 180)
hslhsl(258, 96%, 36%)
oklchoklch(0.378 0.227 279.6)
Closest name: Galactic Highway (#3311bb)Relative luminance 0.0425

Colors that go with #3904b4

Charcoal, Steel Blue and Cobalt 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 →

#7fb404

#0427b4 · #9104b4

#b43904 · #04b439

Split-complementary

Open in tool →

#b49104 · #27b404

#b40427 · #7fb404 · #04b491

Contrast

#3904b4 as textRatioAAAA largeAAAFix
Aaon white
11.35:1passpasspassPasses AAA — no fix needed.
Aaon black
1.85:1failfailfail
  • AA: use #8350fb as the text (4.51:1)
  • AAA: use #a782fc as the text (7.24:1)
  • AA: or shift the background to #a6a6a6 (4.66:1)
  • AAA: or shift the background to #cccccc (7.07:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #3904b4 as the background.

Brands using this color

No public brand in the corpus uses this exact color yet. Extract a brand to add one.

Fonts for this mood

#3904b4 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #3904b4
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 #3904b4 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3904b4-ad9cc4-dfc44e-291f2d-e9ebf1?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