Curves (.fcurve)

Use in the application

The Curves adjustment imports and exports its preset catalogue. Applying a preset changes the current adjustment; editing the catalogue leaves previously authored adjustments unchanged.

File structure

UTF-8 JSON with an explicit format tag and version. The current reader and writer use version 1. The example shows the library envelope; the full reference describes the complete value schemas.

Each presets entry has id, name, optional groupPath and curves with rgb, red, green and blue. Each curve is a flat array: all input x values first, then the matching output y values. [0, 1, 0, 1] is the two-point identity curve.

{
  "format": "focale-curve-presets",
  "version": 1,
  "presets": [
    {
      "id": "curve.user.identity",
      "name": "Identity",
      "curves": {
        "rgb": [
          0,
          1,
          0,
          1
        ],
        "red": [
          0,
          1,
          0,
          1
        ],
        "green": [
          0,
          1,
          0,
          1
        ],
        "blue": [
          0,
          1,
          0,
          1
        ]
      }
    }
  ]
}

Validation and limits

Maximum: 16 MiB and 4,096 entries. Each curve has 2–256 points in the normalized unit square, strictly increasing inputs and both input endpoints 0 and 1. Malformed data rejects the library.

Photoshop interchange

ACV is import-only. Supported Photoshop curves map to the four native channels. Use .fcurve to back up and share the complete Focale preset.

Complete format references

Download the full Markdown specifications in English, including schemas, validation rules and compatibility details.

• Download reusable-presets.md