One of the greatest challenges in outdoor photography is properly exposing for contrasty lighting conditions. It often can be difficult to capture detail in both the highlight and shadow portions of an image because digital cameras are limited by the dynamic range that the camera sensor can record. With landscape photography, it's common for the scene being photographed to exceed the tonal range that the camera can record, and exposure often is a compromise between exposing for detail in either the lighter or darker portions of the image. This ultimately causes an underexposure in the shadow portions or an overexposure in the lighter portions of an image.
Traditionally, landscape photographers turned to graduated neutral-density (ND) filters to help tame the broad tonal range of a scene. Many times, using a graduated ND filter was the only way to create an exposure that would hold detail in both the highlight and shadow portions of an image. Graduated ND filters have potential drawbacks, though. A full set of quality filters and a specific filter holder are expensive, and the filters are time consuming to set up, which can be frustrating when lighting conditions are rapidly changing. Also, graduated ND filters don't work well for all scenes and may darken portions of an image that don't need darkening, sometimes leaving signs of filter use.
While the graduated ND filter always will be a staple in a landscape photographer's bag, digital technologies have made great advancements with regard to image processing and the ways of handling scenes with high contrast. Today, landscape photographers have many options when it comes to handling high-contrast scenes. We've all tried HDR, double-processing RAW files and manually blending exposures in the digital darkroom, and these techniques all produce excellent results when used properly. Often, the results are better than using a real graduated ND filter in the field.
One drawback, though, to using these techniques is that they're sometimes overly complicated for images that only need slight tonal adjustments. It has been said, "Just because you can doesn't mean you should." Do you really need to double-process a RAW file or manually blend two exposures, which results in only in a one- to two-stop change in the lighter portions of the image? You can use a more simple method to achieve the same effect and spend less time in front of your computer monitor.
In this article, I'll show you how to use the Layer Style and Layer Mask features in Photoshop to simulate the effects of using a graduated ND filter, which will darken and intensify specific brighter tones in your images. While not overly complex, the technique is flexible and has a subtle, yet dramatic impact on your images.
Easy Mask Selection
Before starting, I should mention that I use a Windows-based computer, so if you use a Mac, substitute the Command key when I mention the Ctrl key and the Option key for the Alt key.
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Begin by adding a new adjustment layer by dragging the background layer to the Create A New Layer icon at the bottom of the Layers palette. If you already have several layers or you're near the end of your workflow, you can merge the effects of the layers into a single layer by selecting the top-most layer and pressing and holding Ctrl+Alt+Shift+E. I usually rename this layer ND Gradient or something similar. With your ND Gradient layer selected, choose Select from the top menu bar and choose Color Range and then select Highlights from the drop-down menu (Figure 1). The marching ants will appear, and the highlights in your image will be selected.
Usually, just selecting highlights won't give me the tonal range I'm looking for. Sometimes, the portion of the image that needs darkening includes highlights and midtones, but Photoshop won't let you select both simultaneously. A work-around is to select Shadows from the drop-down menu and click the Invert icon. The highlights and midtones are now selected.
With the chosen color range still selected, choose Refine Edge from the Select menu. Adjust the edge of your selection using Feather and Shift Edge. I find that I usually feather my selections between 100 and 250 pixels, depending on the specific image. A broad feathering gives you a larger, gentler blend, which leads to a more natural-looking image. Once you have your selection feathered, shift the edge of the selection until the feathered edge starts just slightly at the transition between the light and dark potions of the image. An edge shift of +25% to +45% usually works well for most images (Figure 2).
Using Layer Styles
After feathering and shifting your selection, convert the selection into a mask by clicking the Add Layer Mask icon at the bottom of the Layers palette. To darken your selection using a Layer Style, double-click the ND Gradient Layer to bring up the Layer Style menu. Choose Gradient Overlay from the Blending Options. You should notice the bottom portion of your selection is darker and the top portion is lighter. Click the Reverse icon to invert the gradient (Figure 3).
I like to fine-tune my gradient transition while still in Blend Mode: Normal. Place your cursor over the image and click and drag the cursor up and down within the image. Notice that as you drag the cursor up and down, you can see the density change in the selection area. This is similar to positioning your graduated ND filter in its holder in the field. Changing the Scale percentage allows you to adjust the abruptness of the change, which is very similar to using a soft-edge or hard-edge graduated ND filter. Lowering the Scale percentage produces a hard-edge filter effect, and raising the Scale percentage is similar to a soft-edge effect.
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To simulate a graduated ND filter, click the Gradient drop-down to edit the gradient (Figure 4). Use the Neutral Density Filter Presets for this technique, so if the Default Presets are showing, click the little arrow icon and choose Neutral Density. When using the presets, I usually start by using the Neutral Density Preset, but depending on the image, I may use any of the other presets. After choosing a preset, notice that the top portion of your image is darkened and the bottom remains unchanged. At this point, you also may want to go back and fine-tune the position of the effect and Scale percentage.
Seeing The Effect
The next step is to change the Gradient Blend Mode to Soft Light. After choosing Soft Light, you can see the full graduated ND effect. One of the benefits of using Soft Light is that it also intensifies contrast. You should notice a slight increase in contrast in the lighter portions of your image. Changing the Opacity and Scale and even the Neutral Density Preset allows you to further fine-tune the effect to your image (Figure 5).
With a little practice, you'll become proficient with feathering and shifting your mask selection. However, if you're not happy with the selection, you always can go back and refine your mask.
To refine the mask, click on the mask to select it and then right-click and choose Refine Mask from the drop-down. Increase or decrease the Feather and Shift Edge until you have a transition that's seamless and that you're happy with (Figure 6). Finally, adjust the Opacity setting to the density effect that you like. Depending on the image, I find that an Opacity setting in the range of 20% to 50% makes for a realistic transition.
Benefits And Limitations
This technique isn't without limitations, though. While it's great for adding density to your highlight and midtone areas, it can't be used to fix blown highlights, and it's not a recovery tool. The technique won't enhance image data that isn't there. Depending on the image, I find the technique to have a workable range equivalent to about one or two stops. For a contrasty scene having a wide dynamic range, your best bet is to get the exposure right in the field using a traditional graduated ND filter or use another processing method, such as HDR or double-processing a RAW file.
Despite the technique's limitations, using the Layer Style and Layer Mask features in Photoshop to simulate a graduated ND filter can make a subtle, yet dramatic difference in the look of your images. Think of it as another tool at your disposal in the digital darkroom. After learning this technique, you can decide for yourself whether to leave your one- or two-stop graduated ND filters in the car on your next landscape photography outing.
Ansley Johnson is a self-taught photographer based in Georgia. You can see more of Johnson's work at ajphoto.zenfolio.com.