Blending Exposures – Lightroom to Photoshop and Back Again

JB_Bio_JCB8775-2By Justin Black
Today’s digital cameras have the ability to capture a tremendous tonal range, which in the case of the Nikon D800 is 14-stops, an incredible 1:16,000 brightness ratio. Even so, from time to time we find that we wish to optimize the exposure for different parts of an image, much the way we used to with graduated neutral-density filters when we were using color transparency film. These days, Photoshop has proven to be a better solution in most cases, so my grad-ND filters tend to languish in the closet. Here’s the technique that I use when I need to blend two exposures with distinct areas of widely differing brightness.
1)    In the field, shoot two RAW exposures on a tripod and without changing camera position, zoom, focus point, or aperture between exposures (as these will affect the pixel-for-pixel registration of the image). One exposure should be exposed to just barely keep the highlights from clipping (exposed to the right, or ETTR). The other should be exposed even lighter to capture more shadow detail. The highlights will probably clip in this lighter exposure, but just make sure that the light mid-tones don’t clip. The judgment as to how light to make the second exposure is subjective and can only be made on the spot based on reviewing the camera histogram. It’s a good idea to shoot a few bracketed exposures to cover the bases.

2)    Import images into Lightroom (LR).

3)    Process each image as you normally would, paying attention primarily to the highlight values in the darker image, and the shadow and mid- tone values in the lighter image. You generally don’t need to worry about correcting clipped highlights in the lighter image or clipped shadows in the darker image, since you probably won’t be using them.

4)    As a starting point, it’s a good idea to set identical values for the following settings:

• White Balance (Temp and Tint)

• Presence (Clarity, Vibrance, Saturation)

• HSL and Color sliders

• Detail (Sharpening, Noise Reduction)

• Lens Corrections

• Effects

• Camera Calibration

The easiest way to set these identically is to select both images and use the Sync Settings function. You can always depart from the synced settings if you wish.


5)    Once you’ve made LR adjustments to each image, select them both. In the LR menu at the top of the screen, go to Photo > Edit In > Open as Layers in Photoshop.

6)    In Photoshop (PS), you’ll see that both images are open as layers, one above the other.

7)    Add a mask to the top image by going to the Layers window, clicking on the top image, and then clicking the mask icon, which looks like a grey box with a white circle on it.

8)    In the Layers menu, click on the white mask symbol to the right of the top image layer. This will set you up to work on the mask.

9)    Select the brush tool, and set the color to black, opacity to 100%, and hardness to zero.

10) Paint on the mask anywhere that you want to hide the top image and let the bottom image show through. You can vary brush size, hardness, and opacity, and switch back and forth between white and black to refine the mask.

11) You should now have two exposures blended into one. At this point, you can add adjustment layers above the original images and proceed with your normal PS workflow to finalize the image, or simply Save As the file back to the original folder that they came from. The composite image will be automatically added to your Lightroom catalog.