# #643b78

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

## Values

- Hex: `#643b78`
- RGB: rgb(100, 59, 120)
- HSL: hsl(280, 34%, 35%)
- OKLCH: oklch(0.428 0.107 313.7)
- Relative luminance: 0.0719
- Nearest named color: Heartless (#623b70, Δ 1.394) — https://brandsweets.com/colors/heartless
- Moods: cool, muted
- Page: https://brandsweets.com/colors/643b78

## Tints & shades

- Tints (toward white): #74458c, #8851a4, #9762b2, #a576bc, #b48ec7, #c2a3d2, #d0b7dc, #ddcce6, #ede4f2, #faf8fc
- Shades (toward black): #5b366d, #523163, #4a2c59, #41274f, #392244, #2d1b37, #25162c, #1c1122, #140c18, #0b070e

## Harmonies

- Complementary: #4f783b
- Analogous: #453b78, #783b6d
- Triadic: #78633b, #3b7863
- Split-complementary: #6d783b, #3b7845
- Tetradic: #78453b, #4f783b, #3b6d78

## Colors that go with #643b78

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 #643b78: softer than #000 and cool enough to feel like part of the same palette. Seen in: Hinge (https://brandsweets.com/colors/brands/hinge-co), Tumblr (https://brandsweets.com/colors/brands/tumblr-com), Harbour (https://brandsweets.com/palettes/cool#harbour), Codecademy (https://brandsweets.com/colors/brands/codecademy-com). — https://brandsweets.com/colors/charcoal
- **Sea Green** #2e8b57 [harmony, pool: complementary] — Sea Green sits directly opposite #643b78 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight. Seen in: Jack Daniel's (https://brandsweets.com/colors/brands/jackdaniels-com). — https://brandsweets.com/colors/seagreen
- **Crimson** #dc143c [pool] — Crimson is paired with #643b78 in 4 real palettes, including Wells Fargo's brand system and Lenovo's brand system, as the lead colour. Seen in: Wells Fargo (https://brandsweets.com/colors/brands/wellsfargo-com), Lenovo (https://brandsweets.com/colors/brands/lenovo-com), Walgreens (https://brandsweets.com/colors/brands/walgreens-com), Codecademy (https://brandsweets.com/colors/brands/codecademy-com). — https://brandsweets.com/colors/crimson
- **Denim** #1560bd [pool] — Designers have shipped Denim with #643b78: 5 real palettes, including Hinge's brand system and HP's brand system, as the accent. Seen in: Hinge (https://brandsweets.com/colors/brands/hinge-co), HP (https://brandsweets.com/colors/brands/hp-com), Slack (https://brandsweets.com/colors/brands/slack-com), Jack Daniel's (https://brandsweets.com/colors/brands/jackdaniels-com). — https://brandsweets.com/colors/denim
- **Royal Blue** #4169e1 [pool] — Royal Blue is paired with #643b78 in 6 real palettes, including Console Light and Wayfair's brand system, as the lead colour. Seen in: Console Light (https://brandsweets.com/palettes/technical#console-light), Wayfair (https://brandsweets.com/colors/brands/wayfair-com), Stripe (https://brandsweets.com/colors/brands/stripe), Zoom (https://brandsweets.com/colors/brands/zoom-us). — https://brandsweets.com/colors/royalblue
- **Taupe** #483c32 [pool] — Taupe is paired with #643b78 in 5 real palettes, including Datadog's brand system and Dusk, as that palette's text colour. Seen in: Datadog (https://brandsweets.com/colors/brands/datadoghq-com), Dusk (https://brandsweets.com/palettes/cool#dusk), Superhuman (https://brandsweets.com/colors/brands/superhuman-com), Blush (https://brandsweets.com/palettes/light#blush). — https://brandsweets.com/colors/taupe
- **Teal** #008080 [harmony, pool: split] — Teal is a split-complement of #643b78: nearly opposite, so it still pops against it, without the vibrating edge of a true complement. Seen in: Stanley (https://brandsweets.com/colors/brands/stanley1913-com), Sapphire & Gold (https://brandsweets.com/palettes/luxury#sapphire-and-gold). — https://brandsweets.com/colors/teal
- **Midnight Blue** #191970 [pool] — 3 real palettes, including First Snow and Microsoft's brand system put Midnight Blue beside #643b78, as that palette's text colour. Seen in: First Snow (https://brandsweets.com/palettes/cool#first-snow), Microsoft (https://brandsweets.com/colors/brands/microsoft-com), Lufthansa (https://brandsweets.com/colors/brands/lufthansa-com). — https://brandsweets.com/colors/midnightblue

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

- On white (#ffffff): 8.61:1 — AA pass, AA-large pass, AAA pass
- On black (#000000): 2.44:1 — AA fail, AA-large fail, AAA fail. Fix: AA: text → #955eb0 (4.51:1); AA: background → #bdbdbd (4.58:1); AAA: text → #b087c4 (7.11:1); AAA: background → #e8e8e8 (7.03:1)

## Palette tool

Open this color locked as the lead with four explored companions: https://brandsweets.com/palettes/new/643b78-b99fc1-b8cb62-2d1f2c-ebe9f1?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: "#643b78" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.