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Curves Tool

Move numeric control points to build a smooth tone curve and apply it to every channel.

Shape the tone curve

Download result
Curve and lookup table
Curve: —
The curve is built with monotone interpolation into a 256 step lookup table and applied on a local canvas.

How to use the Curves Tool

  1. Load the photo you want to tone, then move the five control point sliders.
  2. Watch the curve canvas redraw and the preview update with the new lookup table.
  3. Download the finished PNG once the curve looks right.

Features

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Frequently Asked Questions

Common questions about the free online curves tool.

Levels sets the black, white and mid points only, while curves gives you five control points so you can shape highlights and shadows independently.
Each slider sets the output brightness for one fixed input value, so raising the midtone point lifts the middle of the image only.
Monotone interpolation keeps the curve smooth and prevents it from dipping backwards, which avoids ugly banding and halo artefacts in the photo.
The same lookup table is applied to the red, green and blue channels, so the tone changes while the colour balance stays neutral.
Yes. Every slider you move rebuilds the lookup table and redraws the preview canvas immediately, with no upload or waiting time.
No. The image stays on your device and all the pixel work happens in your browser using a local canvas element.
Click the reset button to put every control point back on the straight identity line and return the photo to its original tone.
Yes. Click the download link to save the current preview as a PNG file with the curve already applied.
Yes. The sliders and both canvases are fully responsive and the tool works in any modern mobile browser.

Last updated: October 10, 2026