BYTETOOLS

Image Curves Editor

Drag a tone curve to reshape shadows, midtones and highlights, per channel or all at once, with S-curve, film fade and cross-process presets built in.

Drop an image to edit its tone curveProcessed locally — never uploaded

Drag inside the box to bend the curve; click empty space to add a point; double-click a point to delete it. Horizontal is input tone, vertical is output tone.

Curve points

Points are interpolated with a monotone cubic spline, so the curve always passes through them and never overshoots between them.

What is the Image Curves Editor?

The ByteTools curves editor is the tone control every photo editor buries in a dialog, running in your browser.

  • Draggable tone curve with add, move and double-click-to-delete points
  • Monotone cubic spline interpolation, so the curve never overshoots
  • Separate curves for RGB, red, green and blue
  • Presets for S-curve contrast, film fade, crushed blacks and cross-process
  • Copyable list of every control point for reuse elsewhere
  • Full-resolution PNG export with 100% in-browser processing

How to use the Image Curves Editor

  1. 1

    Drop an image into the upload area to load it.

  2. 2

    Choose the curve channel — RGB for tone, or red, green or blue for colour grading.

  3. 3

    Drag inside the graph to bend the curve, click empty space to add a point, or double-click a point to delete it.

  4. 4

    Type exact values into the Input and Output boxes and press Add point when you need precision.

  5. 5

    Try a preset for a quick look, then click Download PNG to export the result.

About the Image Curves Editor

The ByteTools curves editor is the tone control every photo editor buries in a dialog, running in your browser. Drag the diagonal line to lift shadows, roll off highlights or build the classic S-curve that adds contrast without clipping. Control points are joined with a monotone cubic spline, so the curve always passes through them and never overshoots between them.

Work on RGB for pure tone, or switch to the red, green or blue curve to grade colour — lifting the blue shadow point is the whole trick behind faded film looks. Five presets, from S-curve contrast through film fade, crushed blacks and cross-process, give you a starting point, and the exact control points are listed beside the graph ready to copy.

Curves are turned into a 256-entry lookup table and applied to canvas pixel data entirely inside your browser, so processing is 100% local and your image is never uploaded to a server. The preview follows your drags in real time, and the download re-renders the curve over the original at full resolution.

Frequently asked questions

What does a curves adjustment do to a photo?

A curve maps every input brightness to a new output brightness. Points above the diagonal make that tonal range brighter and points below it make it darker, so you can lift shadows, darken highlights or steepen the midtones independently of each other.

How do I add contrast with a curve?

Build an S-curve: pull a point in the shadows slightly down and a point in the highlights slightly up. That steepens the midtone slope, which is where contrast is perceived, while leaving the extreme ends alone so nothing clips to pure black or white.

What is the difference between curves and levels?

Levels give you three handles — black point, gamma and white point — so the whole tonal remap follows one fixed shape. Curves let you place as many points as you like anywhere along the range, so you can brighten midtones while leaving highlights untouched, which levels cannot do.

How do I create a faded film look?

Raise the left end of the RGB curve so the darkest tone outputs around 25 to 40 instead of 0, which lifts the blacks to a matte grey. Doing the same on the blue channel only adds the cool shadow tint associated with faded film stock. The Film fade preset does both for you.

Are my photos uploaded to a server?

No. The curve is compiled into a lookup table and applied to canvas pixel data in your own browser, so no image data ever leaves your device. That makes the tool safe to use on client work and private photos.

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