# #efff42

A color — vivid. Deterministic analysis from BrandSweets (no inference).

## Values

- Hex: `#efff42`
- RGB: rgb(239, 255, 66)
- HSL: hsl(65, 100%, 63%)
- OKLCH: oklch(0.957 0.198 114.5)
- Relative luminance: 0.9026
- Nearest named color: Busy Bee (#f4ff00, Δ 1.699) — https://brandsweets.com/colors/busy-bee
- Moods: vivid
- Page: https://brandsweets.com/colors/efff42

## Tints & shades

- Tints (toward white): #f1ff57, #f2ff66, #f4ff7a, #f5ff8a, #f7ff9e, #f8ffad, #faffc2, #fbffd1, #fdffe5, #fefff5
- Shades (toward black): #edff24, #eaff05, #d2e600, #b6c700, #9fad00, #838f00, #677000, #4b5200, #2f3300, #131400

## Harmonies

- Complementary: #5242ff
- Analogous: #ffb042, #91ff42
- Triadic: #42efff, #ff42ef
- Split-complementary: #4291ff, #b042ff
- Tetradic: #42ffb0, #5242ff, #ff4291

## Colors that go with #efff42

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

- **Blue** #0000ff [pool] — 4 real palettes, including Snapchat's brand system and Robinhood's brand system put Blue beside #efff42, as the supporting colour. Seen in: Snapchat (https://brandsweets.com/colors/brands/snapchat-com), Robinhood (https://brandsweets.com/colors/brands/robinhood-com), Bumble (https://brandsweets.com/colors/brands/bumble-com), Binance (https://brandsweets.com/colors/brands/binance-com). — https://brandsweets.com/colors/blue
- **Crimson** #dc143c [pool] — Crimson is paired with #efff42 in 4 real palettes, including Ferrari's brand system and Lay's's brand system, as the lead colour. Seen in: Ferrari (https://brandsweets.com/colors/brands/ferrari-com), Lay's (https://brandsweets.com/colors/brands/lays-com), Tequila Sunrise (https://brandsweets.com/palettes/vivid#tequila-sunrise), Diner (https://brandsweets.com/palettes/vivid#diner). — https://brandsweets.com/colors/crimson
- **Taupe** #483c32 [pool] — Taupe is paired with #efff42 in 4 real palettes, including Calvin Klein's brand system and Tommy Hilfiger's brand system, as the lead colour. Seen in: Calvin Klein (https://brandsweets.com/colors/brands/calvinklein-us), Tommy Hilfiger (https://brandsweets.com/colors/brands/tommy-com), Crayon Box (https://brandsweets.com/palettes/playful#crayon-box), Citrus Grove (https://brandsweets.com/palettes/warm#citrus-grove). — https://brandsweets.com/colors/taupe
- **Violet** #ee82ee [harmony, pool: split] — Violet is a split-complement of #efff42: nearly opposite, so it still pops against it, without the vibrating edge of a true complement. Seen in: Gumroad (https://brandsweets.com/colors/brands/gumroad-com). — https://brandsweets.com/colors/violet
- **Plum** #dda0dd [harmony: complementary] — Plum sits directly opposite #efff42 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight. — https://brandsweets.com/colors/plum
- **Charcoal** #36454f [role, pool] — Charcoal is the body-text near-black for #efff42: its slight blue cast keeps type crisp beside a warm colour where pure #000 looks heavy. Seen in: Zendesk (https://brandsweets.com/colors/brands/zendesk-com), Lagoon (https://brandsweets.com/palettes/vivid#lagoon). — https://brandsweets.com/colors/charcoal
- **Deep Pink** #ff1493 [pool] — 3 real palettes, including Arcade and JetBrains's brand system put Deep Pink beside #efff42, as the lead colour. Seen in: Arcade (https://brandsweets.com/palettes/vivid#arcade), JetBrains (https://brandsweets.com/colors/brands/jetbrains-com), Night Market (https://brandsweets.com/palettes/vivid#night-market). — https://brandsweets.com/colors/deeppink
- **Denim** #1560bd [pool] — Designers have shipped Denim with #efff42: 3 real palettes, including Ikea's brand system and FIFA's brand system, as the accent. Seen in: Ikea (https://brandsweets.com/colors/brands/ikea-com), FIFA (https://brandsweets.com/colors/brands/fifa-com), LEGO (https://brandsweets.com/colors/brands/lego-com). — https://brandsweets.com/colors/denim

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

- On white (#ffffff): 1.1:1 — AA fail, AA-large fail, AAA fail. Fix: AA: text → #707a00 (4.7:1); AA: background → #6e6e6e (4.63:1); AAA: text → #545c00 (7.22:1); AAA: background → #525252 (7.09:1)
- On black (#000000): 19.05:1 — AA pass, AA-large pass, AAA pass

## Curated palettes containing it

- **Arcade** (neon, vivid, dark, bold) — #ff2e88, #00f0ff, #faff00, #0a0a14, #f5f5ff — Hot pink, cyan and acid yellow on near-black — cabinet-glow neon; the black surface is what makes the colours light up. — tool: https://brandsweets.com/palettes/new/ff2e88-00f0ff-faff00-0a0a14-f5f5ff — collection: https://brandsweets.com/palettes/neon

## Palette tool

Open this color locked as the lead with four explored companions: https://brandsweets.com/palettes/new/efff42-b8bea2-4e88df-262d1f-f1eee9?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: "#efff42" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.