How to Create an HDR Image in GIMP

Combining bracketed exposures into a High Dynamic Range (HDR) image in GIMP allows you to capture the full tonal range of a scene, preserving detail in both deep shadows and bright highlights. This guide provides a straightforward method for importing bracketed photos as layers, aligning them, blending them using layer masks in 32-bit floating-point precision, and making final adjustments to produce a balanced, realistic HDR photograph.

Step 1: Set Image Precision

For the best dynamic range and color depth without banding, configure GIMP to use high bit-depth processing:

  1. Open GIMP.
  2. Go to Image > Precision.
  3. Select 32-bit floating point and Linear light (or Perceptual, depending on your preferred color workflow).

Step 2: Open Bracketed Exposures as Layers

  1. Go to File > Open as Layers...
  2. Select your bracketed photos (typically three or more shots: underexposed, normally exposed, and overexposed) and click Open.
  3. In the Layers panel, reorder the images from brightest to darkest, placing the normally exposed image in the middle, the overexposed image at the bottom, and the underexposed image at the top.

Step 3: Align the Images

If the photos were taken handheld or if there is slight movement between frames, align them to prevent ghosting:

  1. Select the top layer and change its Mode to Difference. If the layers are not aligned, edges will appear bright.
  2. Use the Move Tool (shortcut: M) to nudge the layer with the arrow keys until the overlapping details turn completely black or as dark as possible.
  3. Switch the layer Mode back to Normal.
  4. Repeat this alignment check for each exposure layer relative to the base layer.

Step 4: Blend the Highlights (Underexposed Layer)

  1. Hide all layers except the middle (normal) and top (underexposed) layers.
  2. Right-click the top (underexposed) layer and select Add Layer Mask.
  3. In the dialog, select Grayscale copy of layer and check the Invert mask box (or keep it uninverted depending on whether you want the mask to target bright areas). To bring in only the highlights from the dark image, select Grayscale copy of layer without inverting.
  4. Click Add. The dark image will now only show through in the brightest regions, recovering clipped highlights.

Step 5: Blend the Shadows (Overexposed Layer)

  1. Make the bottom (overexposed) layer visible.
  2. Right-click the middle (normal) layer and select Add Layer Mask.
  3. Choose Grayscale copy of layer and check Invert mask.
  4. Click Add. This allows the shadows of the base image to become transparent, revealing the clean, shadow-boosted details from the overexposed layer beneath it.

Step 6: Refine Masks and Adjust Exposure

  1. Click directly on any layer mask thumbnail in the Layers panel to edit it.
  2. Apply Colors > Curves or Colors > Levels to the mask itself to tighten or soften the blending transitions.
  3. Use a soft Paintbrush set to black or white with low opacity to manually paint over areas where you want more or less detail from a specific exposure.

Step 7: Tone Mapping and Final Output

  1. Right-click any layer in the Layers panel and select New from Visible to create a merged layer at the top of your stack.
  2. Select the merged layer and navigate to Colors > Exposure or Colors > Curves to adjust global contrast, midtone brightness, and saturation.
  3. Once satisfied with the final image, go to File > Export As... and choose your preferred format, such as TIFF for archiving or JPEG for sharing.