Slate Workspace
Open in tool →Slate on slate with a single blue — the productivity-app look where the interface disappears behind the work.
Color
#646f90
#646f90
hex
#646f90rgb
rgb(100, 111, 144)hsl
hsl(225, 18%, 48%)oklch
oklch(0.545 0.053 270.2)Closest name: Dark Prince (#6b6c89)Relative luminance 0.1609
Colors that go with #646f90
Charcoal, Sea Green and Dark Olive Green lead the list. Each partner is a real named colour with the reason it works — a wheel relationship, a neutral that carries it, or a pairing lifted from a palette or brand system that actually shipped — and every pair opens in the palette tool.
Charcoal #36454f
neutralshippedCharcoal is the text near-black for #646f90: softer than #000 and cool enough to feel like part of the same palette.
Sea Green #2e8b57
triadicshippedSea Green completes a triad with #646f90 — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash.
Dark Olive Green #556b2f
complementaryshippedDark Olive Green sits directly opposite #646f90 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Amber #ffbf00
shippedAmber is paired with #646f90 in 6 real palettes, including Beach Hut and Lemon Squeezy's brand system, as the supporting colour.
Champagne #f7e7ce
shipped6 real palettes, including Midnight Luxe and Forest Floor put Champagne beside #646f90, as that palette's text colour.
Cobalt Blue #0047ab
shippedDesigners have shipped Cobalt Blue with #646f90: 6 real palettes, including Fintech Trust and Ink & Paper, as the lead colour.
Copper #b87333
shippedDesigners have shipped Copper with #646f90: 6 real palettes, including Dusk and Riverbed, as the accent.
Crimson #dc143c
shippedCrimson is paired with #646f90 in 12 real palettes, including Retro Pop and Marvel's brand system, as the lead colour.
Real palettes that use #646f90
Tints & shades
Harmonies
Contrast
| #646f90 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 4.98:1 | pass | pass | fail |
|
Aaon black | 4.22:1 | fail | pass | fail |
Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #646f90 as the background.
Brands using this color
No public brand in the corpus uses this exact color yet. Extract a brand to add one.
Palettes built around it
Clinic
Open in tool →Teal reads clinical without the coldness of pure blue; the coral accent adds warmth for reassurance moments.
Campus
Open in tool →Institutional blue with a highlighter-amber accent — trustworthy for parents, lively enough for students.
mcpConnect your agent — build around #646f90
live endpointPoint any MCP client at the shared colors endpoint and your agent gets the same engine as this page — direct_palette, edit_direction, check_palette, check_contrast — read-only, no key. Every direction it proposes comes with a /colors/d/… link: open it, lock what you like, paste the link back, and the agent edits rather than re-rolls.
endpoint
https://mcp.brandsweets.com/colors/mcpclaude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
try this prompt
›analyze #646f90 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
tool url
/palettes/new/646f90-9ca1c4-df754e-221f2d-e9eff1?lock=0&style=vibrantWant the agent to remember your picks and write them into a living brand? Create a free BrandSweets workspace.
Machine-readable: color.md