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The color wheel: hue, chroma, and lightness

How Tone Caliper's wheel maps hue, chroma, and lightness, how your photo's colors appear on it, and how to zoom and navigate.

The color wheel is the main surface in the Color tab (shortcut 2). It plots your photo's colors so you can select one and shift it. This page explains what the wheel shows and how to move around it; for the drag-a-pin workflow see Editing colors.

The three axes

Any color on the wheel is described by three separate quantities. Keeping them separate lets you change one without disturbing the others.

Hue — the angle

Hue is the angle around the center. Traveling around the rim moves through the spectrum, from reds to greens to blues and back.

Chroma — distance from the center

Chroma is what many people call saturation: distance from the middle outward. The exact center is neutral gray, with no color at all; colors grow more vivid the farther out they sit toward the rim.

Lightness — the separate strip

How light a color is lives on its own Lightness strip beneath the wheel, not on the disc. Because the disc is drawn at a single fixed lightness, a dot's brightness on the disc is only for display — each color still carries its own true lightness, which you read on the strip and in the photo. Double-click the strip to reset it.

A tour of the wheel: hue runs around the rim, chroma from the neutral gray center out to the vivid edge, and lightness on the strip below the disc.

More consistent movement across colors

The wheel is built on OKLab, a color space designed to keep color changes more visually consistent. In practice this means a drag of a given length tends to produce a similar-looking shift whether you start from a green or a blue, and rotating a hue tends to hold its lightness fairly steady rather than drifting brighter or darker. Movement stays more visually consistent from one color to the next, which makes it easier to judge edits by eye across the frame.

Your photo on the wheel

The soft cloud of colored dots on the disc is your photo: every pixel plotted by its hue and chroma. Reading the cloud helps you plan a grade before you place a pin — you can see greens split into two clumps, or a sky that is really a gradient of blues. As you drag a pin, the cloud flows with it, so the wheel and the image stay in step.

The pixel cloud is your photo: every pixel plotted by hue and chroma, so the wheel and the image show the same colors at once.

A second image's colors can sit on the disc alongside your own, as a fixed target to grade toward — see Reference image.

Getting around

Most photos use only part of the disc, so the wheel opens already framed on your colors.

  1. Press the Fit button (F, "Frame the photo's colors") to zoom to the colors actually in the photo.
  2. Press the 1:1 button (0, "Full wheel") to pull back to the entire disc.
  3. Zoom in to pull apart tones that sit almost on top of each other, so you can place a pin on one without catching the other.

When you are zoomed in, a faint ring-and-spoke graticule and a colored compass edge keep you oriented — which direction is warmer, where neutral sits, and where any off-screen pins point.

It usually helps to set the scene — exposure, white balance, and contrast — before grading color on the wheel. See Tone and contrast.

Try this with your own photo — Tone Caliper is a free trial on Windows and macOS.

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