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Contrast checker

The short version: Set a background and a foreground. Read the verdict. If it fails, control-click the swatch you want to fix and pick a target ratio. Done.

Opening the checker

  • Press your Check Contrast hotkey.
  • Click the menu bar icon and choose Check Contrast….

The window remembers your last colors, so if you’re iterating on the same pair across sessions, you don’t have to set them up again.

Setting the colors

Each color has a row with three affordances:

  • The swatch / eyedropper — click to sample a color from anywhere on screen.
  • The text input — type or paste any color string ColorCopy can parse (hex, rgb(), hsl(), or a CSS color name).
  • The native color well — opens macOS’s system color picker for sliders and saved palettes.

Swap Colors at the bottom flips foreground and background, useful for checking dark-mode variants.

Reading the verdict (WCAG 2)

WCAG 2 is the contrast standard most projects target today. ColorCopy shows the contrast ratio (e.g. 4.62:1) and how it scores against the four common thresholds:

  • AA Normal — needs 4.5:1 (body text under 18 pt / 14 pt bold).
  • AA Large — needs 3:1 (text 18 pt+ or 14 pt+ bold).
  • AAA Normal — needs 7:1 (the stricter target for body text).
  • AAA Large — needs 4.5:1 (the stricter target for large text).

Reading the verdict (APCA)

APCA is the perceptual contrast metric being evaluated for WCAG 3. It reports a single number called Lc — positive for dark text on light backgrounds, negative for light on dark.

Switch to APCA from the algorithm picker. ColorCopy shows the Lc value and a guideline range based on common APCA-recommended targets for body, large, and display text.

Use APCA when you’re working in a design system that targets it, or when you want a more perceptually accurate read on whether your text is legible.

The sample preview

The big preview at the top renders your chosen colors with three lines of text: a heading, a body line, and a caption. All three are editable — click them and type your real product copy. That’s often what reveals a contrast problem (or proves one isn’t real).

Edited the text and want to start over? A revert button appears in the corner of the preview as soon as you change anything. One click puts the defaults back.

Auto-fixing a failure

This is the part most people don’t know about.

Right-click (or control-click) either swatch and you’ll get a context menu with target ratios:

  • 3:1 — AA Large / AAA Large
  • 4.5:1 — AA Normal / AAA Large
  • 7:1 — AAA Normal
  • (or a free-form target if you need a non-standard value)

Pick one and ColorCopy adjusts that color to the exact ratio you chose, against the other one. It nudges luminance up or down (whichever brings the ratio in range) without changing the hue more than it has to. Your accent stays your accent — it just becomes more readable.

APCA auto-fix works the same way: pick a target Lc and ColorCopy hits it.

Closing

Press Esc or Cmd-W, or click Done.

Free tier limits

Sampling a color (using the eyedropper from inside the contrast window) counts as one pick against the monthly cap. Adjusting the algorithm, swapping colors, or auto-fixing does not.

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