Photoshop

Merge images to HDR

Use the Merge To HDR command to combine multiple images (with different exposures) of the same image or scene, capturing the dynamic range of a scene in a single HDR image. You can choose to save the merged image as a 32‑bpc HDR image.

Note: It’s also possible to use the Merge To HDR command to save the merged image as an 8‑ or 16‑bpc image. However, only a 32‑bpc image can store all the HDR image data; 8‑ and 16‑bpc images will be clipped.

For information on taking photos to merge into HDR images, see Take photos for merging to HDR, below.

  1. Do one of the following:

    • (Photoshop) Choose File > Automate > Merge To HDR.

    • (Bridge) Select the images you want to use and choose Tools > Photoshop > Merge To HDR. Skip to step 3.

  2. In the Merge To HDR dialog box, click Browse, browse to select the images, and click Open.

    To remove an item, select it in the Merge To HDR dialog box and click Remove.

    Note: If you want to add a folder of images or images that are open in Photoshop, choose Folder or Open Files from the Use menu.
  3. (Optional) Select the Attempt To Automatically Align Source Images option if you held the camera in your hands when you photographed the multiple images.
  4. Click OK.

    A second Merge To HDR dialog box displays thumbnails of the images being used in the merged result, a preview of the merged result, a Bit Depth menu, and a slider for setting the white point preview.

  5. If necessary, do one of the following to set the view options for the merged result preview:

    • Click the Minus or Plus buttons below the preview image to zoom out or zoom in.

    • Choose a view percentage or mode from the pop‑up menu below the preview image.

  6. (Optional) Deselect or select the thumbnails in the Sources filmstrip to specify which images to use in the merged image.
    Selecting the thumbnails in the Sources filmstrip

  7. Choose a bit depth for the merged image from the Bit Depth menu.

    Be sure to choose 32 Bits/Channel if you want the merged image to store the entire dynamic range data of the HDR image. 8‑bits and (non-floating point) 16‑bpc images files cannot store the entire range of luminance values in an HDR image.

  8. Move the slider below the histogram to preview the merged image.

    Moving the slider adjusts the image preview only. All the HDR image data remains intact in the merged image file. If you’re saving the merged image as 32‑bpc, the preview adjustment is stored in the HDR image file and applied whenever the file is opened in Photoshop. The preview adjustment is always accessible and adjustable by choosing View > 32‑Bit Preview Options.

  9. Click OK to create the merged image.

    If you chose to save the merged image as an 8‑bits or 16‑bpc image, the HDR Conversion dialog box opens. Make the exposure and contrast corrections to produce an image with the dynamic range (tonal range) you want. For more information, see Convert from 32 bits to 8 or 16 bpc.

Take photos for merging to HDR

Keep the following tips in mind when you take photos to be combined with the Merge To HDR command:

  • Secure the camera to a tripod.

  • Take enough photos to cover the full dynamic range of the scene. You can try taking at least five to seven photos, but you might need to take more exposures depending on the dynamic range of the scene. The minimum number of photos should be three.

  • Vary the shutter speed to create different exposures. Changing the aperture changes the depth of field in each exposure and can produce lower-quality results. Changing the ISO or aperture may also cause noise or vignetting in the image.

  • In general, don’t use your camera’s auto-bracket feature, because the exposure changes are usually too small.

  • The exposure differences between the photos should be one or two EV (exposure value) steps apart (equivalent to about one or two f‑stops apart).

  • Don’t vary the lighting; for instance, don’t use a flash in one exposure but not the next.

  • Make sure that nothing is moving in the scene. Exposure Merge works only with differently exposed images of the identical scene.