If you’ve ever taken pictures outdoors, you probably understand how difficult it can be to get a properly exposed photo — if the ground is properly exposed, the sky is totally blown out. Professional photographers often use neutral density filters to solve the problem, but they can be expensive.
Fortunately, digital post-processing gives you a great way to get perfectly exposed landscapes.
Shooting for Exposure Blending
The idea behind exposure blending is pretty simple: when light conditions don’t allow you to properly expose an entire scene, you can combine two or more photos that have been exposed to different levels of light to balance the exposure in the final image.
If you’re familiar with HDR photography, you might wonder why you’d go through the trouble of exposure blending when you can just flip the switch to “HDR on” or use HDR software to increase the range between the lightest and darkest parts of your photo. While this is an option, automated HDR processing doesn’t always create the best photos . While some HDR algorithms can do a good job, many of them end up with crazy colors and uneven tones. Manually blending exposures usually results in much more natural images.
To show you just how useful exposure blending can be, I’ve picked a sample photo to use throughout this article. Let’s take a look at the exposure in the first shot of this sunset that I took (with a shutter speed of 1/200 second):
This photo is underexposed : the sun and the clouds look pretty good, but the entire foreground is totally lost.
I took another photo of the same scene with different exposure settings (shutter speed of 1/20), and this is what I got:
This one is overexposed : now you can see the foreground, but the sky is completely blown out, and the dark, moody feel of the silhouettes on the horizon has been lost. I couldn’t get a shot that gave me the detail that I wanted in both areas of the photo.
If you want to try exposure blending, buying a tripod is a must. If you have a very steady hand, you might be able to get shots that are similar enough to work, but the vast majority of the time a tripod will be necessary. For exposure blending, two to three exposures of the same scene are usually sufficient—but the more you have, the more you have to work with, so shoot away.
Blending for Perfect Exposures
Exposure blending is actually a pretty simple process. I’ll go through it here in six steps.
1. Open both images in your photo editing software (I’ll be using Pixelmator here, but you can follow these same steps in Photoshop, GIMP, or any other editing software).
2. Click into one of the images, copy it, click into the other, and paste it. It will go into a new layer on top of the other image. For these photos, I chose to use the darker exposure as the top layer, but you can experiment and see which order works best for you and your photos.
3. Add an opaque layer mask to the top image, or add a transparent mask. Select the layer mask and use the paint bucket tool to fill in the entire layer with black so that only the bottom layer is visible (when using a layer mask, painting with white will make the connected layer transparent where the paint was applied, while painting with black makes it opaque).
4. Paint with white (on the layer mask) over the part of your photo that you’d like to replace with portions of the other layer—here, I’m painting over the background with a white brush to bring the deeper colors of the sky through to the underexposed image.
As you can see, I’ve now completely replaced the original, bright background with the better-exposed, darker one. The line between the field and the shadowed trees and houses is unnaturally sharp now, though—it looks a bit strange. So we’ll use the gradient tool to fix it.
5. On the layer mask, paint some black over the bottom of the area that you’ve replaced to bring more of the lower layer back into view (notice in the photo above that the line is no longer on the horizon, but slightly above).
6. Still on the layer mask, use the gradient tool to draw a gradient from white to black across the area that needs to be blended (I’ve hidden the background layer here so it’s easier to see the gradient). This will allow the under-exposed image to fade into the over-exposed one, creating a better transition between the two.
Now, the transition between the sky and the ground looks a lot more natural. You can experiment with how much of the photo you draw the gradient over—I used a very small slice in this case, but you could go a lot further and get a more pronounced transition.
You can also do more complicated things with more powerful tools, like selecting areas by luminosity in Photoshop so that you can replace only the darkest or lightest areas for a more balanced exposure. You can also selectively touch up areas with a paintbrush or other tool to lighten or darken specific areas.
Now that you’ve separated the two (or more) parts of the photo, you can also adjust each section individually by selecting a layer and making adjustments in brightness, contrast, levels, curves, or whatever else you need to do to get the picture you had been hoping for — this is where the real editing begins!
Now that you have an idea of how to get started with photo blending, go ahead and try it out. Start with two exposures and work your way up — experiment with different opacity levels of brushes, the size of gradients, and anything else you can think of. The best way to learn how to create great photos is to head out with your camera and play around with your photos until you find what works for you. Not everyone likes the same style of photography, so feel free to develop something completely your own!
Have you used exposure blending to get better landscape shots? Do you have any tips that make the process easier? Share your thoughts below!