Configure OpenEXR Half-Precision Export in GIMP

This guide explains how to configure GIMP to export OpenEXR images using 16-bit half-precision floating-point format. By following these straightforward steps, you will learn how to verify your canvas bit depth, access the export dialog, and select the appropriate precision and compression settings to maintain high dynamic range data while optimizing file size for 3D and visual effects workflows.

1. Set the Image Precision in GIMP

Before exporting, ensure your project is operating at the desired floating-point precision to avoid unexpected clipping or color space conversions.

  1. Open or create your image in GIMP.
  2. Navigate to the top menu and select Image > Precision.
  3. Choose 16-bit floating point (half precision). You can also work in 32-bit floating point and downsample during export, but setting it here guarantees you preview the dynamic range accurately.

2. Open the Export Dialog

Once your artwork or render is ready:

  1. Click File > Export As... (or press Shift + Ctrl + E).
  2. Name your file and append the .exr extension to the filename (e.g., render_output.exr).
  3. Alternatively, expand the Select File Type (By Extension) list at the bottom of the window and select OpenEXR image.
  4. Click the Export button to launch the OpenEXR configuration window.

3. Configure the OpenEXR Settings

The OpenEXR dialog controls how image channels, precision, and compression are packaged into the output file.

  1. Precision / Data Format: Locate the data format dropdown or toggle. By default, GIMP may set this to 32-bit float (single precision). Change this setting to HALF (16-bit floating point).
  2. Compression: Select an appropriate compression algorithm based on your pipeline requirements:
    • ZIP / ZIPS: Lossless, ideal for images with large areas of flat color or subtle gradients.
    • PIZ: Lossless, highly effective for grainy images and photographic renders.
    • RLE: Fast, simple run-length encoding.
    • None: Uncompressed, resulting in the largest file size.
  3. Verify that any extra channels (such as Alpha) are enabled if your project requires transparency.

4. Finalize the Export

Click Export to generate the file. The resulting .exr file will retain negative values and dynamic range beyond standard display limits (0.0 to 1.0) while consuming half the storage space of a full 32-bit float EXR file.