# #ef4539

A color — warm, vivid, playful, bold. Deterministic analysis from BrandSweets (no inference).

## Values

- Hex: `#ef4539`
- RGB: rgb(239, 69, 57)
- HSL: hsl(4, 85%, 58%)
- OKLCH: oklch(0.636 0.208 28.5)
- Relative luminance: 0.229
- Nearest named color: Blazing (#e94e41, Δ 1.508) — https://brandsweets.com/colors/blazing
- Moods: warm, vivid, playful, bold
- Page: https://brandsweets.com/colors/ef4539

## Tints & shades

- Tints (toward white): #f0574c, #f2685f, #f47a71, #f58c84, #f79e97, #f8afaa, #fac1bd, #fbd3d0, #fde4e3, #fef6f6
- Shades (toward black): #ed2f21, #de2012, #c61c10, #aa180e, #92150c, #7b110a, #5e0d08, #470a06, #2a0603, #130302

## Harmonies

- Complementary: #39e3ef
- Analogous: #ef3988, #efa039
- Triadic: #39ef45, #4539ef
- Split-complementary: #39efa0, #3988ef
- Tetradic: #88ef39, #39e3ef, #a039ef

## Colors that go with #ef4539

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

- **Cadet Blue** #5f9ea0 [harmony, pool: complementary] — Cadet Blue sits directly opposite #ef4539 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight. Seen in: Diner (https://brandsweets.com/palettes/vivid#diner), Alpine (https://brandsweets.com/palettes/cool#alpine), Clean Beauty (https://brandsweets.com/palettes/minimal#clean-beauty), Dusk (https://brandsweets.com/palettes/cool#dusk). — https://brandsweets.com/colors/cadetblue
- **Charcoal** #36454f [role, pool] — Charcoal is the body-text near-black for #ef4539: its slight blue cast keeps type crisp beside a warm colour where pure #000 looks heavy. Seen in: Audi (https://brandsweets.com/colors/brands/audi-com), Frost & Ember (https://brandsweets.com/palettes/bold#frost-and-ember), Tumblr (https://brandsweets.com/colors/brands/tumblr-com), HubSpot (https://brandsweets.com/colors/brands/hubspot-com). — https://brandsweets.com/colors/charcoal
- **Steel Blue** #4682b4 [harmony, pool: split] — Steel Blue is a split-complement of #ef4539: nearly opposite, so it still pops against it, without the vibrating edge of a true complement. Seen in: Retro Pop (https://brandsweets.com/palettes/playful#retro-pop), Launch Orange (https://brandsweets.com/palettes/bold#launch-orange), Substack (https://brandsweets.com/colors/brands/substack-com), Wired (https://brandsweets.com/colors/brands/wired-com). — https://brandsweets.com/colors/steelblue
- **Amber** #ffbf00 [pool] — Amber is paired with #ef4539 in 7 real palettes, including Google's brand system and Heatwave, as the accent. Seen in: Google (https://brandsweets.com/colors/brands/google-com), Heatwave (https://brandsweets.com/palettes/warm#heatwave), Ember (https://brandsweets.com/palettes/bold#ember), Wired (https://brandsweets.com/colors/brands/wired-com). — https://brandsweets.com/colors/amber
- **Blue** #0000ff [pool] — 9 real palettes, including Glossier's brand system and Doordash's brand system put Blue beside #ef4539, as the accent. Seen in: Glossier (https://brandsweets.com/colors/brands/glossier-com), Doordash (https://brandsweets.com/colors/brands/doordash-com), Monzo (https://brandsweets.com/colors/brands/monzo-com), native Cybersecurity (https://brandsweets.com/colors/brands/crowdstrike-com). — https://brandsweets.com/colors/blue
- **Cobalt Blue** #0047ab [pool] — Designers have shipped Cobalt Blue with #ef4539: 5 real palettes, including NASA's brand system and Tide's brand system, as the lead colour. Seen in: NASA (https://brandsweets.com/colors/brands/nasa-gov), Tide (https://brandsweets.com/colors/brands/tide-com), Walgreens (https://brandsweets.com/colors/brands/walgreens-com), Behance (https://brandsweets.com/colors/brands/behance-net). — https://brandsweets.com/colors/cobalt
- **Denim** #1560bd [pool] — Designers have shipped Denim with #ef4539: 16 real palettes, including ElevenLabs's brand system and Postman's brand system, as the accent. Seen in: ElevenLabs (https://brandsweets.com/colors/brands/elevenlabs-io), Postman (https://brandsweets.com/colors/brands/postman-com), PlanetScale (https://brandsweets.com/colors/brands/planetscale-com), L'Oréal (https://brandsweets.com/colors/brands/loreal-com). — https://brandsweets.com/colors/denim
- **Dodger Blue** #1e90ff [pool] — Designers have shipped Dodger Blue with #ef4539: 7 real palettes, including Google's brand system and Figma's brand system, as the lead colour. Seen in: Google (https://brandsweets.com/colors/brands/google-com), Figma (https://brandsweets.com/colors/brands/figma), Databricks (https://brandsweets.com/colors/brands/databricks-com), Replit (https://brandsweets.com/colors/brands/replit). — https://brandsweets.com/colors/dodgerblue

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

- On white (#ffffff): 3.76:1 — AA fail, AA-large pass, AAA fail. Fix: AA: text → #e72113 (4.54:1); AA: background → #1c1c1c (4.53:1); AAA: text → #af190e (7.08:1)
- On black (#000000): 5.58:1 — AA pass, AA-large pass, AAA fail. Fix: AAA: text → #f26d63 (7.14:1)

## Brands using this color

- **Google** — secondary #ea4335 (Δ 1.121) — https://brandsweets.com/colors/brands/google-com
- **Clerk** — secondary #ef4444 (Δ 1.156) — https://brandsweets.com/colors/brands/clerk-com
- **NASA** — accent #f64137 (Δ 1.294) — https://brandsweets.com/colors/brands/nasa-gov

## Fonts for this mood

- warm: https://brandsweets.com/fonts/mood/warm
- playful: https://brandsweets.com/fonts/mood/playful
- bold: https://brandsweets.com/fonts/mood/bold

## Palette tool

Open this color locked as the lead with four explored companions: https://brandsweets.com/palettes/new/ef4539-c4a39c-62cb9f-2d261f-f1e9ed?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: "#ef4539" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.