Dusk
Open in tool →Slate blue with a copper accent — calm, professional, slightly editorial; suits consultancies and journals.
Color
#515b81
#515b81
hex
#515b81rgb
rgb(81, 91, 129)hsl
hsl(228, 23%, 41%)oklch
oklch(0.479 0.063 272.5)Closest name: Deep Indigo (#4c567a)Relative luminance 0.1082
Colors that go with #515b81
Charcoal, Sea Green and Steel Blue 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 #515b81: softer than #000 and cool enough to feel like part of the same palette.
Sea Green #2e8b57
triadicshippedSea Green completes a triad with #515b81 — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash.
Steel Blue #4682b4
analogousshippedSteel Blue is #515b81's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces.
Amber #ffbf00
shippedAmber is paired with #515b81 in 4 real palettes, including McDonald's's brand system and Lemon Squeezy's brand system, as the lead colour.
Blue #0000ff
shipped4 real palettes, including Activision's brand system and Tesco's brand system put Blue beside #515b81, as the accent.
Cobalt Blue #0047ab
shippedDesigners have shipped Cobalt Blue with #515b81: 6 real palettes, including Fintech Trust and Ink & Paper, as the lead colour.
Copper #b87333
shippedDesigners have shipped Copper with #515b81: 4 real palettes, including Dusk and Desert Road, as the accent.
Crimson #dc143c
shippedCrimson is paired with #515b81 in 15 real palettes, including Wells Fargo's brand system and Costco's brand system, as the lead colour.
Real palettes that use #515b81
Tints & shades
Harmonies
Contrast
| #515b81 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 6.64:1 | pass | pass | fail |
|
Aaon black | 3.16:1 | 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 #515b81 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
mcpConnect your agent — build around #515b81
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 #515b81 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
tool url
/palettes/new/515b81-9c9fc4-df7c4e-231f2d-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