# #643b81

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

## Values

- Hex: `#643b81`
- RGB: rgb(100, 59, 129)
- HSL: hsl(275, 37%, 37%)
- OKLCH: oklch(0.434 0.118 309.4)
- Relative luminance: 0.0742
- Nearest named color: Lords of the Night (#664488, Δ 2.414) — https://brandsweets.com/colors/lords-of-the-night
- Moods: cool, modern
- Page: https://brandsweets.com/colors/643b81

## Tints & shades

- Tints (toward white): #744596, #854fab, #9362b7, #a277c0, #b28fcc, #c1a4d5, #cfb9df, #decee9, #ece3f2, #faf8fc
- Shades (toward black): #5c3777, #513069, #492b5e, #412754, #392249, #2e1b3b, #261631, #1e1226, #130b18, #0b060e

## Harmonies

- Complementary: #59813b
- Analogous: #413b81, #813b7b
- Triadic: #81643b, #3b8164
- Split-complementary: #7b813b, #3b8141
- Tetradic: #81413b, #59813b, #3b7b81

## Colors that go with #643b81

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 #643b81: softer than #000 and cool enough to feel like part of the same palette. Seen in: Hinge (https://brandsweets.com/colors/brands/hinge-co), Harbour (https://brandsweets.com/palettes/cool#harbour), Tumblr (https://brandsweets.com/colors/brands/tumblr-com), dbt Labs (https://brandsweets.com/colors/brands/getdbt-com). — https://brandsweets.com/colors/charcoal
- **Midnight Blue** #191970 [pool] — 5 real palettes, including First Snow and Microsoft's brand system put Midnight Blue beside #643b81, 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), Kraken (https://brandsweets.com/colors/brands/kraken-com), Lufthansa (https://brandsweets.com/colors/brands/lufthansa-com). — https://brandsweets.com/colors/midnightblue
- **Royal Blue** #4169e1 [pool] — Royal Blue is paired with #643b81 in 4 real palettes, including Wayfair's brand system and Console Light, as the supporting colour. Seen in: Wayfair (https://brandsweets.com/colors/brands/wayfair-com), Console Light (https://brandsweets.com/palettes/technical#console-light), Stripe (https://brandsweets.com/colors/brands/stripe), Nokia (https://brandsweets.com/colors/brands/nokia-com). — https://brandsweets.com/colors/royalblue
- **Taupe** #483c32 [pool] — Taupe is paired with #643b81 in 4 real palettes, including Datadog's brand system and Superhuman's brand system, as that palette's text colour. Seen in: Datadog (https://brandsweets.com/colors/brands/datadoghq-com), Superhuman (https://brandsweets.com/colors/brands/superhuman-com), Dusk (https://brandsweets.com/palettes/cool#dusk), Blush (https://brandsweets.com/palettes/light#blush). — https://brandsweets.com/colors/taupe
- **Tomato** #ff6347 [pool] — 4 real palettes, including Golden Hour and FedEx's brand system put Tomato beside #643b81, as the supporting colour. Seen in: Golden Hour (https://brandsweets.com/palettes/warm#golden-hour), FedEx (https://brandsweets.com/colors/brands/fedex-com), Harley-Davidson (https://brandsweets.com/colors/brands/harley-davidson-com), dbt Labs (https://brandsweets.com/colors/brands/getdbt-com). — https://brandsweets.com/colors/tomato
- **Dark Olive Green** #556b2f [harmony: complementary] — Dark Olive Green sits directly opposite #643b81 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/darkolivegreen
- **Crimson** #dc143c [pool] — Crimson is paired with #643b81 in 3 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). — https://brandsweets.com/colors/crimson
- **Denim** #1560bd [pool] — Designers have shipped Denim with #643b81: 3 real palettes, including Hinge's brand system and Slack's brand system, as the accent. Seen in: Hinge (https://brandsweets.com/colors/brands/hinge-co), Slack (https://brandsweets.com/colors/brands/slack-com), HP (https://brandsweets.com/colors/brands/hp-com). — https://brandsweets.com/colors/denim

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

- On white (#ffffff): 8.45:1 — AA pass, AA-large pass, AAA pass
- On black (#000000): 2.48:1 — AA fail, AA-large fail, AAA fail. Fix: AA: text → #9362b7 (4.67:1); AA: background → #bfbfbf (4.6:1); AAA: text → #ae88c8 (7.16:1); AAA: background → #ebebeb (7.09:1)

## Fonts for this mood

- 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/643b81-b89cc4-c0cb62-2d1f2d-eae9f1?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: "#643b81" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.