# #4271ff

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

## Values

- Hex: `#4271ff`
- RGB: rgb(66, 113, 255)
- HSL: hsl(225, 100%, 63%)
- OKLCH: oklch(0.598 0.217 266)
- Relative luminance: 0.2019
- Nearest named color: Blue Öyster Cult (#5577ee, Δ 3.655) — https://brandsweets.com/colors/blue-oyster-cult
- Moods: cool, vivid, technical, modern
- Page: https://brandsweets.com/colors/4271ff

## Tints & shades

- Tints (toward white): #5781ff, #668cff, #7a9cff, #8aa7ff, #9eb6ff, #adc2ff, #c2d1ff, #d1ddff, #e5ecff, #f5f7ff
- Shades (toward black): #245bff, #0544ff, #0039e6, #0032c7, #002bad, #00248f, #001c70, #001452, #000d33, #000514

## Harmonies

- Complementary: #ffd042
- Analogous: #42d0ff, #7142ff
- Triadic: #ff4271, #71ff42
- Split-complementary: #ff7142, #d0ff42
- Tetradic: #ff42d0, #ffd042, #42ff71

## Colors that go with #4271ff

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 #4271ff: softer than #000 and cool enough to feel like part of the same palette. Seen in: Docker (https://brandsweets.com/colors/brands/docker-com), Zoom (https://brandsweets.com/colors/brands/zoom-us), Disney (https://brandsweets.com/colors/brands/disney-com), Hinge (https://brandsweets.com/colors/brands/hinge-co). — https://brandsweets.com/colors/charcoal
- **Crimson** #dc143c [harmony, pool: triadic] — Crimson completes a triad with #4271ff — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash. Seen in: Behance (https://brandsweets.com/colors/brands/behance-net), WWE (https://brandsweets.com/colors/brands/wwe-com), Toyota (https://brandsweets.com/colors/brands/toyota-com), Chase (https://brandsweets.com/colors/brands/chase-com). — https://brandsweets.com/colors/crimson
- **Copper** #b87333 [harmony, pool: complementary] — Copper sits directly opposite #4271ff 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). — https://brandsweets.com/colors/copper
- **Amber** #ffbf00 [pool] — Amber is paired with #4271ff in 9 real palettes, including Mastodon hosted on mastodon.social's brand system and Google's brand system, as the accent. Seen in: Mastodon hosted on mastodon.social (https://brandsweets.com/colors/brands/mastodon-social), Google (https://brandsweets.com/colors/brands/google-com), Walmart (https://brandsweets.com/colors/brands/walmart-com), NBA (https://brandsweets.com/colors/brands/nba-com). — https://brandsweets.com/colors/amber
- **Blue** #0000ff [pool] — 13 real palettes, including Penpot's brand system and Cargo's brand system put Blue beside #4271ff, as the supporting colour. Seen in: Penpot (https://brandsweets.com/colors/brands/penpot-app), Cargo (https://brandsweets.com/colors/brands/cargo-site), Samsung (https://brandsweets.com/colors/brands/samsung-com), MongoDB (https://brandsweets.com/colors/brands/mongodb-com). — https://brandsweets.com/colors/blue
- **Cobalt Blue** #0047ab [pool] — Designers have shipped Cobalt Blue with #4271ff: 10 real palettes, including Behance's brand system and Carrefour's brand system, as the supporting colour. Seen in: Behance (https://brandsweets.com/colors/brands/behance-net), Carrefour (https://brandsweets.com/colors/brands/carrefour-com), Nivea (https://brandsweets.com/colors/brands/nivea-com), Nokia (https://brandsweets.com/colors/brands/nokia-com). — https://brandsweets.com/colors/cobalt
- **Cornflower Blue** #6495ed [pool] — Designers have shipped Cornflower Blue with #4271ff: 5 real palettes, including Webflow's brand system and Mastodon hosted on mastodon.social's brand system, as the accent. Seen in: Webflow (https://brandsweets.com/colors/brands/webflow-com), Mastodon hosted on mastodon.social (https://brandsweets.com/colors/brands/mastodon-social), Roblox (https://brandsweets.com/colors/brands/roblox-com), NBA (https://brandsweets.com/colors/brands/nba-com). — https://brandsweets.com/colors/cornflowerblue
- **Deep Sky Blue** #00bfff [pool] — Designers have shipped Deep Sky Blue with #4271ff: 8 real palettes, including Elastic's brand system and Calm's brand system, as the supporting colour. Seen in: Elastic (https://brandsweets.com/colors/brands/elastic-co), Calm (https://brandsweets.com/colors/brands/calm-com), Venmo (https://brandsweets.com/colors/brands/venmo-com), Patreon (https://brandsweets.com/colors/brands/patreon-com). — https://brandsweets.com/colors/deepskyblue

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

- On white (#ffffff): 4.17:1 — AA fail, AA-large pass, AAA fail. Fix: AA: text → #3366ff (4.68:1); AA: background → #0f0f0f (4.6:1); AAA: text → #003df5 (7.03:1)
- On black (#000000): 5.04:1 — AA pass, AA-large pass, AAA fail. Fix: AAA: text → #6b90ff (7.06:1)

## Fonts for this mood

- technical: https://brandsweets.com/fonts/mood/technical
- 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/4271ff-9ca1c4-df754e-221f2d-e9eff1?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: "#4271ff" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.