# #51517b

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

## Values

- Hex: `#51517b`
- RGB: rgb(81, 81, 123)
- HSL: hsl(240, 21%, 40%)
- OKLCH: oklch(0.453 0.068 283.3)
- Relative luminance: 0.0906
- Nearest named color: Dusk (#4e5481, Δ 1.18) — https://brandsweets.com/colors/dusk
- Moods: cool, muted
- Page: https://brandsweets.com/colors/51517b

## Tints & shades

- Tints (toward white): #5d5d8e, #6b6b9e, #7a7aa8, #8d8db4, #9f9fc1, #b2b2cd, #c4c4d9, #d4d4e3, #e6e6ef, #f9f9fb
- Shades (toward black): #49496f, #424266, #3a3a59, #343450, #2c2c44, #242438, #1e1e2e, #161622, #101019, #08080c

## Harmonies

- Complementary: #7b7b51
- Analogous: #51667b, #66517b
- Triadic: #7b5151, #517b51
- Split-complementary: #7b6651, #667b51
- Tetradic: #7b5166, #7b7b51, #517b66

## Colors that go with #51517b

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

- **Sea Green** #2e8b57 [harmony, pool: split] — Sea Green is a split-complement of #51517b: nearly opposite, so it still pops against it, without the vibrating edge of a true complement. Seen in: Subaru (https://brandsweets.com/colors/brands/subaru-com), Jack Daniel's (https://brandsweets.com/colors/brands/jackdaniels-com), Netflix (https://brandsweets.com/colors/brands/netflix), Paramount+ (https://brandsweets.com/colors/brands/paramountplus-com). — https://brandsweets.com/colors/seagreen
- **Steel Blue** #4682b4 [harmony, pool: analogous] — Steel Blue is #51517b's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces. Seen in: Capital One (https://brandsweets.com/colors/brands/capitalone-com), Auth0 (https://brandsweets.com/colors/brands/auth0-com), American Express (https://brandsweets.com/colors/brands/americanexpress-com), Discover (https://brandsweets.com/colors/brands/discover-com). — https://brandsweets.com/colors/steelblue
- **Teal** #008080 [harmony, pool: triadic] — Teal completes a triad with #51517b — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash. Seen in: Stanley (https://brandsweets.com/colors/brands/stanley1913-com), Gusto (https://brandsweets.com/colors/brands/gusto-com), Sapphire & Gold (https://brandsweets.com/palettes/luxury#sapphire-and-gold), Magazine Ochre (https://brandsweets.com/palettes/editorial#magazine-ochre). — https://brandsweets.com/colors/teal
- **Blue** #0000ff [pool] — 5 real palettes, including Tesco's brand system and CVS's brand system put Blue beside #51517b, as the supporting colour. Seen in: Tesco (https://brandsweets.com/colors/brands/tesco-com), CVS (https://brandsweets.com/colors/brands/cvs-com), Activision (https://brandsweets.com/colors/brands/activision-com), Alaska Airlines (https://brandsweets.com/colors/brands/alaskaair-com). — https://brandsweets.com/colors/blue
- **Crimson** #dc143c [pool] — Crimson is paired with #51517b in 10 real palettes, including Wells Fargo's brand system and Codecademy's brand system, as the lead colour. Seen in: Wells Fargo (https://brandsweets.com/colors/brands/wellsfargo-com), Codecademy (https://brandsweets.com/colors/brands/codecademy-com), Walgreens (https://brandsweets.com/colors/brands/walgreens-com), Costco (https://brandsweets.com/colors/brands/costco-com). — https://brandsweets.com/colors/crimson
- **Denim** #1560bd [pool] — Designers have shipped Denim with #51517b: 16 real palettes, including HP's brand system and The New York Times's brand system, as the accent. Seen in: HP (https://brandsweets.com/colors/brands/hp-com), The New York Times (https://brandsweets.com/colors/brands/nytimes-com), Dutch Bros (https://brandsweets.com/colors/brands/dutchbros-com), Hinge (https://brandsweets.com/colors/brands/hinge-co). — https://brandsweets.com/colors/denim
- **Firebrick** #b22222 [pool] — Designers have shipped Firebrick with #51517b: 4 real palettes, including Fireside and Campbell's's brand system, as the lead colour. Seen in: Fireside (https://brandsweets.com/palettes/dark#fireside), Campbell's (https://brandsweets.com/colors/brands/campbells-com), Wendy's (https://brandsweets.com/colors/brands/wendys-com), AT&T (https://brandsweets.com/colors/brands/att-com). — https://brandsweets.com/colors/firebrick
- **White Smoke** #f5f5f5 [role] — White Smoke is the surface for #51517b: a clean near-white with no warm cast, so the cool hue stays clear instead of drifting muddy. — https://brandsweets.com/colors/whitesmoke

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

- On white (#ffffff): 7.47:1 — AA pass, AA-large pass, AAA pass
- On black (#000000): 2.81:1 — AA fail, AA-large fail, AAA fail. Fix: AA: text → #7171a2 (4.59:1); AA: background → #c9c9c9 (4.51:1); AAA: text → #9393b8 (7.11:1); AAA: background → #fafafa (7.15:1)

## Palette tool

Open this color locked as the lead with four explored companions: https://brandsweets.com/palettes/new/51517b-a19cc4-df994e-251f2d-e9edf1?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: "#51517b" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.