# #428bb3

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

## Values

- Hex: `#428bb3`
- RGB: rgb(66, 139, 179)
- HSL: hsl(201, 46%, 48%)
- OKLCH: oklch(0.607 0.095 235.3)
- Relative luminance: 0.2288
- Nearest named color: steelblue (#4682b4, Δ 2.639) — https://brandsweets.com/colors/steelblue
- Moods: cool, modern
- Page: https://brandsweets.com/colors/428bb3

## Tints & shades

- Tints (toward white): #5098be, #63a3c5, #75aecc, #88b9d3, #9ac4da, #adcfe1, #c0dae8, #d2e5ee, #e5f0f5, #f8fbfc
- Shades (toward black): #3d80a4, #367191, #306682, #295770, #244b61, #1e4052, #17313f, #122630, #0b171e, #060c0f

## Harmonies

- Complementary: #b36a42
- Analogous: #42b3a2, #4253b3
- Triadic: #b3428b, #8bb342
- Split-complementary: #b34253, #b3a242
- Tetradic: #a242b3, #b36a42, #53b342

## Colors that go with #428bb3

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 #428bb3: 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), Auth0 (https://brandsweets.com/colors/brands/auth0-com), Dusty Blue (https://brandsweets.com/palettes/cool#dusty-blue), Plaid (https://brandsweets.com/colors/brands/plaid-com). — https://brandsweets.com/colors/charcoal
- **Copper** #b87333 [harmony, pool: complementary] — Copper sits directly opposite #428bb3 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight. Seen in: Notion (https://brandsweets.com/colors/brands/notion), Dusk (https://brandsweets.com/palettes/cool#dusk), Riverbed (https://brandsweets.com/palettes/muted#riverbed), Atelier (https://brandsweets.com/palettes/elegant#atelier). — https://brandsweets.com/colors/copper
- **Royal Blue** #4169e1 [harmony, pool: analogous] — Royal Blue is #428bb3's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces. Seen in: Slate Workspace (https://brandsweets.com/palettes/minimal#slate-workspace), Confluent (https://brandsweets.com/colors/brands/confluent-io), Elastic (https://brandsweets.com/colors/brands/elastic-co), HashiCorp (https://brandsweets.com/colors/brands/hashicorp-com). — https://brandsweets.com/colors/royalblue
- **Amber** #ffbf00 [pool] — Amber is paired with #428bb3 in 8 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), McDonald's (https://brandsweets.com/colors/brands/mcdonalds-com). — https://brandsweets.com/colors/amber
- **Blue** #0000ff [pool] — 4 real palettes, including Qualcomm's brand system and Readymag's brand system put Blue beside #428bb3, as the accent. Seen in: Qualcomm (https://brandsweets.com/colors/brands/qualcomm-com), Readymag (https://brandsweets.com/colors/brands/readymag-com), Activision (https://brandsweets.com/colors/brands/activision-com), Unity (https://brandsweets.com/colors/brands/unity-com). — https://brandsweets.com/colors/blue
- **Cobalt Blue** #0047ab [pool] — Designers have shipped Cobalt Blue with #428bb3: 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 #428bb3 in 9 real palettes, including Retro Pop and NASCAR's brand system, as the lead colour. Seen in: Retro Pop (https://brandsweets.com/palettes/playful#retro-pop), NASCAR (https://brandsweets.com/colors/brands/nascar-com), Wendy's (https://brandsweets.com/colors/brands/wendys-com), Redfin (https://brandsweets.com/colors/brands/redfin-com). — https://brandsweets.com/colors/crimson
- **Deep Sky Blue** #00bfff [pool] — Designers have shipped Deep Sky Blue with #428bb3: 7 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

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

- On white (#ffffff): 3.77:1 — AA fail, AA-large pass, AAA fail. Fix: AA: text → #3b7da0 (4.54:1); AA: background → #1c1c1c (4.52:1); AAA: text → #2c5d77 (7.14:1)
- On black (#000000): 5.58:1 — AA pass, AA-large pass, AAA fail. Fix: AAA: text → #5b9ec2 (7.11:1)

## 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/428bb3-9cb1c4-df4e62-1f222d-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: "#428bb3" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.