Master Manual Exposure Blending With This Foolproof Photoshop Workflow

With modern HDR-blending algorithms making exposure blending so quick and easy, manual exposure blending may seem like an outdated skill for landscape photographers. However, automated software doesn't always produce the cleanest results. In this article, we'll discuss a foolproof workflow for manual exposure blending that will give you total control over your images and ensure results of the highest quality. The good news is that this workflow doesn't require any third-party panels or difficult luminosity masking! 

Below is a set of exposure-bracketed images, straight out of camera with no edits applied, that were captured as a single frame in a larger panorama. These images were all captured at base ISO to ensure maximum image quality. 

As you can see, the light in this scene was very difficult to capture, and even the best modern sensors would have required exposure bracketing to capture the full range of light without introducing noise into the shadows or clipping the brightest highlights. We will use this difficult exposure blend as an example of the occasional shortcomings of automated exposure-blending algorithms, such as Lightroom's "HDR Photomerge" feature. The image below is the result of Adobe's HDR blending. Admittedly, Lightroom typically does an excellent job with exposure blending, and I use it on the majority of my exposure-bracketed images. However, as you can see, it doesn't always produce the best results when difficult light is involved. When processed with the desired final settings, the blended output file produces a harsh transition in the bright highlights. Additionally, there is no way to be certain whether the algorithm is blending noisy data into the shadows and midtones that could come back to haunt you later in your processing. 

Luckily, for those photographers interested in developing a fine level of control over their exposure blending, we have created a workflow that is predictable, repeatable, and foolproof. This method will guarantee the best image quality and blending possible for difficult scenes such as this one. 

Step One: Process the Base Image

To start with, we need to identify our base image. This will be the image with the brightest exposure, in which the shadows were fully exposed to the right side of the histogram. In my image sequence above, this would be the fourth image, on the far right. Please feel free to follow along with your exposure-bracketed images. The first step in this workflow is to maximize the dynamic range of the base image by dropping the highlights and whites sliders down and raising the shadows and blacks sliders up. This step is critical to ensuring we don't leave any exposure data behind when we bring these images into Photoshop for manual blending. We are essentially aiming to create a low-contrast, blended image that will serve as an excellent base for processing the image to taste later in your workflow. Next, we will make any other adjustments that need to happen while we have access to the raw image data, such as temperature, tint, and sharpening. 

Step Two: Sync Settings and Match Exposures

Next, we will sync these settings across all of our images in the exposure bracket. To do this, first select your base image in the loupe, hold shift on your keyboard, and click the image at the opposite end of the bracket to select all of the images. You must select the base image first for the Sync feature to work properly. Next, simply click the sync button below your editing panels in the bottom right corner of your screen. In the dialogue box, choose "Check All" and click "Synchronize." Next, we need to match the exposure level of each image. To do this, with all of the images still selected, go to Settings > Match Total Exposures. See the series of images below to get an idea of how your bracketed images should look at this point in the process. 

Step Three: Open and Align Images in Photoshop 

It is now time to bring the images into Photoshop for manual blending, which is not as scary as it sounds. With each image still selected, right-click on one of the images and click Edit In > Open As Layers In Photoshop. All of your images will now be imported to Photoshop as individual layers within one project. Make sure that your layers are arranged so that the base image we identified earlier is at the bottom of the layer stack and the rest of the layers follow the sequence of the exposure bracket. If you are paranoid like me or if you shot the exposure bracket handheld, align the images now by selecting each image and going to Edit > Auto-Align. In the dialogue box, select "Auto" and deselect "Vignette Removal" and "Geometric Distortion." Feel free to skip this step if you used a sturdy tripod and are confident that your images are already aligned to the pixel. I never skip alignment because you never know if the images shifted at the pixel level during the capture process. 

Step Four: Manual Exposure Blending Using Blend if

Next, we will begin our manual blending process using an underutilized Photoshop feature called Blend if. First, turn off all of your layers except for the base layer and the one directly above it. Next, right-click the layer above the base layer and click "Blending Options." You can also double-click the space to the right of the layer name. In the Layer Style dialogue box, in the bottom center, you will see a box with the heading "Blend if." Make sure that "Gray" is selected in the dropdown list. Next, move the dialogue box to the side so you can see your image. Finally, we will use the "Underlying Layer" slider to blend lost highlight data into the blown-out base layer. Grab the black slider and start to drag it to the right until you have blended out all of the noisy shadow data. There will be a clear delineation between the data in the base layer and the layer above. To smooth this transition, hold "Alt" on your keyboard and click either half of the black slider to split the slider in two. Once split, the slider will feather the transition between the two layers. See below for an example of how your sliders should look at this point in the workflow. Once you are happy with the blending transition, click OK. 

Step Five: Repeat for All Layers

Next, we will repeat this process for each layer in the exposure bracket, making sure to turn on each respective layer as you go. Do not turn off the layers below. Be aware that the Blend if sliders will require different values for each image. You will need to rely on visual feedback to achieve smooth blending between each layer. This is where we gain control over the blending process compared to the automated HDR blending in Lightroom. After you have successfully blended all of the layers, if desired, you can adjust the opacity of each layer to get the final result you are looking for in the brightest highlights. The image below on the left is the result after blending, and the image on the right shows the final result after I adjusted the opacity of the layers to produce a more natural final result. 

Congratulations! You have just completed a manual exposure blend. Remember that this technique isn't necessary for all exposure blending and only the most difficult scenes will require it. Still, the beauty of this workflow is that it is predictable and repeatable while offering total control over the blending process, which you may appreciate even for easier exposure blends. Third-party panels and luminosity masking can deliver mixed results and require difficult, inelegant workflows that need to be adjusted for each image. The Blend if sliders are quite powerful once you become familiar with how they work and aren't as scary or confusing as they seem. They have completely replaced luminosity masking in my toolbox, not to mention providing countless other uses in my processing. As mentioned before, the example image for this article is part of a greater panorama (see above) in which we used the Blend if sliders to blend every frame before merging the panorama. Once you have blended your exposures, think of the resulting image as a blank canvas on which you can begin your creative processing with the confidence that you are working with the full dynamic range of data.