Color

#1d428b

#1d428b
hex#1d428b
rgbrgb(29, 66, 139)
hslhsl(220, 65%, 33%)
oklchoklch(0.397 0.129 262.1)
Closest name: Cascade Twilight (#234893)Relative luminance 0.0602

Colors that go with #1d428b

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 →

#8b661d

#1d798b · #301d8b

#8b1d42 · #428b1d

Split-complementary

Open in tool →

#8b301d · #798b1d

#8b1d79 · #8b661d · #1d8b30

Contrast

#1d428b as textRatioAAAA largeAAAFix
Aaon white
9.53:1passpasspassPasses AAA — no fix needed.
Aaon black
2.2:1failfailfail
  • AA: use #4273d7 as the text (4.67:1)
  • AAA: use #7096e1 as the text (7.14:1)
  • AA: or shift the background to #b3b3b3 (4.54:1)
  • AAA: or shift the background to #dedede (7.08:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #1d428b as the background.

Brands using this color

Fonts for this mood

#1d428b reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #1d428b
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 #1d428b and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/1d428b-9ca5c4-df694e-211f2d-e9f0f1?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