# #428fb3

A color — cool, modern. Deterministic analysis from BrandSweets (no inference).

## Values

- Hex: `#428fb3`
- RGB: rgb(66, 143, 179)
- HSL: hsl(199, 46%, 48%)
- OKLCH: oklch(0.617 0.093 231.2)
- Relative luminance: 0.2406
- Nearest named color: Blue Moon (#3992a8, Δ 2.27) — https://brandsweets.com/colors/blue-moon
- Moods: cool, modern
- Page: https://brandsweets.com/colors/428fb3

## Tints & shades

- Tints (toward white): #509bbe, #63a6c5, #75b1cc, #88bbd3, #9ac6da, #add0e1, #c0dbe8, #d2e6ee, #e5f0f5, #f8fbfc
- Shades (toward black): #3d83a4, #367491, #306882, #295970, #244d61, #1e4252, #17333f, #122730, #0b181e, #060c0f

## Harmonies

- Complementary: #b36642
- Analogous: #42b39e, #4257b3
- Triadic: #b3428f, #8fb342
- Split-complementary: #b34257, #b39e42
- Tetradic: #9e42b3, #b36642, #57b342

## Colors that go with #428fb3

Named partners (harmony on the OKLCH wheel, co-occurrence in curated palettes and brand systems, and the neutrals that carry it), best first:

- **Charcoal** #36454f [role, pool] — Charcoal is the text near-black for #428fb3: softer than #000 and cool enough to feel like part of the same palette. Seen in: Beach Hut (https://brandsweets.com/palettes/light#beach-hut), Dusty Blue (https://brandsweets.com/palettes/cool#dusty-blue), Auth0 (https://brandsweets.com/colors/brands/auth0-com), Bloomberg (https://brandsweets.com/colors/brands/bloomberg-com). — https://brandsweets.com/colors/charcoal
- **Copper** #b87333 [harmony, pool: complementary] — Copper sits directly opposite #428fb3 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight. Seen in: Dusk (https://brandsweets.com/palettes/cool#dusk), Notion (https://brandsweets.com/colors/brands/notion), Atelier (https://brandsweets.com/palettes/elegant#atelier), Riverbed (https://brandsweets.com/palettes/muted#riverbed). — https://brandsweets.com/colors/copper
- **Amber** #ffbf00 [pool] — Amber is paired with #428fb3 in 6 real palettes, including Beach Hut and Wired's brand system, as the supporting colour. Seen in: Beach Hut (https://brandsweets.com/palettes/light#beach-hut), Wired (https://brandsweets.com/colors/brands/wired-com), Lemon Squeezy (https://brandsweets.com/colors/brands/lemonsqueezy-com), Google (https://brandsweets.com/colors/brands/google-com). — https://brandsweets.com/colors/amber
- **Cobalt Blue** #0047ab [pool] — Designers have shipped Cobalt Blue with #428fb3: 6 real palettes, including Hershey's's brand system and Glacier, as the supporting colour. Seen in: Hershey's (https://brandsweets.com/colors/brands/hersheys-com), Glacier (https://brandsweets.com/palettes/cool#glacier), General Mills (https://brandsweets.com/colors/brands/generalmills-com), Fintech Trust (https://brandsweets.com/palettes/cool#fintech-trust). — https://brandsweets.com/colors/cobalt
- **Crimson** #dc143c [pool] — Crimson is paired with #428fb3 in 9 real palettes, including Retro Pop and Redfin's brand system, as the lead colour. Seen in: Retro Pop (https://brandsweets.com/palettes/playful#retro-pop), Redfin (https://brandsweets.com/colors/brands/redfin-com), NASCAR (https://brandsweets.com/colors/brands/nascar-com), Diner (https://brandsweets.com/palettes/vivid#diner). — https://brandsweets.com/colors/crimson
- **Deep Sky Blue** #00bfff [pool] — Designers have shipped Deep Sky Blue with #428fb3: 8 real palettes, including Telegram's brand system and Astro's brand system, as the lead colour. Seen in: Telegram (https://brandsweets.com/colors/brands/telegram-org), Astro (https://brandsweets.com/colors/brands/astro-build), Deep Water (https://brandsweets.com/palettes/dark#deep-water), Patreon (https://brandsweets.com/colors/brands/patreon-com). — https://brandsweets.com/colors/deepskyblue
- **Denim** #1560bd [pool] — Designers have shipped Denim with #428fb3: 16 real palettes, including Gopro's brand system and Discover's brand system, as the lead colour. Seen in: Gopro (https://brandsweets.com/colors/brands/gopro-com), Discover (https://brandsweets.com/colors/brands/discover-com), American Express (https://brandsweets.com/colors/brands/americanexpress-com), Peacock (https://brandsweets.com/palettes/vivid#peacock). — https://brandsweets.com/colors/denim
- **Goldenrod** #daa520 [pool] — Goldenrod shows up next to #428fb3 in 6 real palettes, including Ledger Dark and Noir Beauty, as the lead colour. Seen in: Ledger Dark (https://brandsweets.com/palettes/dark#ledger-dark), Noir Beauty (https://brandsweets.com/palettes/dark#noir-beauty), Sapphire & Gold (https://brandsweets.com/palettes/luxury#sapphire-and-gold), Chevrolet (https://brandsweets.com/colors/brands/chevrolet-com). — https://brandsweets.com/colors/goldenrod

## Contrast (WCAG 2.x, as text)

- On white (#ffffff): 3.61:1 — AA fail, AA-large pass, AAA fail. Fix: AA: text → #3a7d9c (4.57:1); AA: background → #1f1f1f (4.56:1); AAA: text → #2b5c73 (7.29:1)
- On black (#000000): 5.81:1 — AA pass, AA-large pass, AAA fail. Fix: AAA: text → #57a0c1 (7.2:1)

## Fonts for this mood

- modern: https://brandsweets.com/fonts/mood/modern

## Palette tool

Open this color locked as the lead with four explored companions: https://brandsweets.com/palettes/new/428fb3-9cb3c4-df4e66-1f232d-e9f1f0?lock=0&style=vibrant
(Humans lock/regenerate in the tool; the URL is the state — read `lock=` back to see what they kept.)

## Connect an agent

Point any MCP client at the BrandSweets colors endpoint for the same engine:

- Endpoint: https://mcp.brandsweets.com/colors/mcp
- Tools: `analyze_color` (e.g. `analyze_color({ color: "#428fb3" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.