Colour to colour

Royal Blue to Medium Sea Green gradient

Royal Blue (#4169e1) into Medium Sea Green (#3cb371) — 111° apart on the OKLCH hue wheel. Below: the same two stops interpolated in OKLab and in OKLCH, side by side, because the difference is real and most generators never let you see it; then an eased version and a mesh, each with the worst-case contrast for white and black text. The engine's own pick for this pair is oklab — both colours are in the palette and the hue gap is small enough that the straight line stays clean.

Royal Blue → Medium Sea Green
black text · worst 4.33:1 · AA large
white 2.66 failsblack 4.33 AA largebanding high

OKLab and OKLCH, side by side

Aa

A straight line through the a/b plane: the two hues meet halfway and desaturate a little at the midpoint. The safe default — it is what CSS and Tailwind default to.

white 2.66 failsblack 4.33 AA largebanding high
css
linear-gradient(135deg in oklab, #4169e1 0%, #3cb371 100%)
Aa

OKLCH (shorter hue)

Open in maker →

Chroma and hue interpolate separately, so the midpoint keeps its saturation and the hue travels the short way round the wheel — richer, and it can pass through hues neither colour has.

white 2.67 failsblack 4.33 AA largebanding high
css
linear-gradient(135deg in oklch shorter hue, #4169e1 0%, #3cb371 100%)

And the sRGB line most tools draw, for comparison — the number is the chroma that survives at the dullest point.

sRGB50%
OKLab55%
OKLCH66%

Eased and mesh

Aa

Eased (soft)

Open in maker →

A cubic-bezier(.4, 0, .6, 1) mix ratio baked into 15 stops: the transition lingers on each colour and moves faster through the middle, which is what makes a gradient read as designed rather than default.

white 2.66 failsblack 4.33 AA largebanding high
css
linear-gradient(135deg in oklab, #4169e1 0%, #416be0 8.28%, #3f6fdc 16.03%, #3d75d6 23.35%, #3b7cce 30.32%, #3984c5 37.03%, #378cbb 43.56%, #3693b0 50%, #369ba4 56.44%, #37a198 62.97%, #38a78d 69.68%, #39ac82 76.65%, #3bb079 83.97%, #3cb273 91.72%, #3cb371 100%)
Aa

Both colours as stacked radials over a base, laid out by a seeded Poisson-disc sampler — the same seed gives the same mesh forever. Exports as CSS, SVG and PNG.

white 3.35 AA largeblack 4.93 AAbanding high
css
background-color: #3693b0;
background-image: radial-gradient(circle farthest-corner at 99.29% 72.33%, rgba(65, 105, 225, 0.767) 0%, rgba(65, 105, 225, 0) 51.6%), radial-gradient(circle farthest-corner at 76.33% 32.35%, rgba(60, 179, 113, 0.735) 0%, rgba(60, 179, 113, 0) 45.53%);
background-image: radial-gradient(circle farthest-corner at 99.29% 72.33%, oklch(from #4169e1 l c h / 0.7672) 0%, rgb(from #4169e1 r g b / 0) 51.6%), radial-gradient(circle farthest-corner at 76.33% 32.35%, oklch(from #3cb371 l c h / 0.7346) 0%, rgb(from #3cb371 r g b / 0) 45.53%);

Report

  • white ink: worst 2.66:1 at 100% (fails AA); black ink: worst 4.33:1 at 0% (AA-large only) → use black text.
  • Body text fails AA everywhere on this gradient; large text (≥24px / 19px bold) is fine. Add a scrim or lower the chroma for body copy.
  • Banding high: ~13px bands at 1440px — add grain 27 (≈2% soft-light noise) or shorten the ramp.

Export

css
.gradient {
  background-image: linear-gradient(135deg, #4169e1 0%, #3f70da 7.14%, #3d77d4 14.29%, #3b7dcd 21.43%, #3983c6 28.57%, #3889bf 35.71%, #378eb7 42.86%, #3693b0 50%, #3698a8 57.14%, #369da0 64.29%, #37a298 71.43%, #38a68f 78.57%, #39ab86 85.71%, #3aaf7c 92.86%, #3cb371 100%);
  background-image: linear-gradient(135deg in oklab, #4169e1 0%, #3cb371 100%);
}
tailwind v4
bg-linear-to-br/oklab from-[#4169e1] to-[#3cb371]
svg
<svg xmlns="http://www.w3.org/2000/svg" width="1440" height="600" viewBox="0 0 1440 600"><defs><linearGradient id="bs-gradient" gradientUnits="userSpaceOnUse" x1="210" y1="-210" x2="1230" y2="810"><stop offset="0%" stop-color="#4169e1"/><stop offset="7.14%" stop-color="#3f70da"/><stop offset="14.29%" stop-color="#3d77d4"/><stop offset="21.43%" stop-color="#3b7dcd"/><stop offset="28.57%" stop-color="#3983c6"/><stop offset="35.71%" stop-color="#3889bf"/><stop offset="42.86%" stop-color="#378eb7"/><stop offset="50%" stop-color="#3693b0"/><stop offset="57.14%" stop-color="#3698a8"/><stop offset="64.29%" stop-color="#369da0"/><stop offset="71.43%" stop-color="#37a298"/><stop offset="78.57%" stop-color="#38a68f"/><stop offset="85.71%" stop-color="#39ab86"/><stop offset="92.86%" stop-color="#3aaf7c"/><stop offset="100%" stop-color="#3cb371"/></linearGradient></defs><rect width="1440" height="600" fill="url(#bs-gradient)"/></svg>
dtcg
{
  "royalblue-to-mediumseagreen": {
    "$type": "gradient",
    "$value": [
      {
        "color": {
          "colorSpace": "srgb",
          "components": [
            0.255,
            0.412,
            0.882
          ],
          "hex": "#4169e1"
        },
        "position": 0
      },
      {
        "color": {
          "colorSpace": "srgb",
          "components": [
            0.235,
            0.702,
            0.443
          ],
          "hex": "#3cb371"
        },
        "position": 1
      }
    ],
    "$extensions": {
      "com.brandsweets": {
        "kind": "linear",
        "css": "linear-gradient(135deg in oklab, #4169e1 0%, #3cb371 100%)",
        "interpolation": "oklab",
        "angle": 135,
        "name": "royalblue-to-mediumseagreen",
        "contrast": {
          "white": {
            "ratio": 2.664,
            "at": 0.9968,
            "passesAA": false,
            "passesAALarge": false
          },
          "black": {
            "ratio": 4.333,
            "at": 0,
            "passesAA": false,
            "passesAALarge": true
          },
          "suggestedInk": "#000000"
        }
      }
    },
    "$description": "Royal Blue to Medium Sea Green, interpolated in oklab."
  }
}

More from Royal Blue

mcpConnect your agent to the gradient engine
live endpoint

Point any MCP client at the shared gradients endpoint and your agent gets the same engine as this page — make_gradient returns CSS with the interpolation space, Tailwind v4, SVG, a PNG URL, a DTCG token and the contrast report in one call; brand_gradients derives the whole contact sheet from a brand or a palette. Read-only, no key. Every gradient is a /gradients/new/… link: open it, refine, paste it back.

endpointhttps://mcp.brandsweets.com/gradients/mcp
claude mcp add --transport http brandsweets-gradients https://mcp.brandsweets.com/gradients/mcp
try this prompt

make a royal blue to medium sea green hero gradient in oklch that passes AA for white text, with grain if it bands

Want the agent to remember your picks and write them into a living brand? Create a free BrandSweets workspace.

Machine-readable: gradients.md