Creating Realistic High Dynamic Range Photos
High Dynamic Range (HDR) photography exploded in popularity several years ago and continues to captivate new and experienced photographers. Most people are struck by the extreme contrast and dramatic look of HDR images. With programs like Photomatix, virtually anyone with a digital camera can combine a series of images and extend the overall tonal range of a scene.
You can also enhance the perceived dynamic range of a scene by combining multiple images into a single composite. In this walk through, I demonstrate techniques for manually combining several photographs taken at varying exposures into a final HDR composite. I also share several of my favorite processing techniques for landscape photography. Image compositing takes patience and skill, but the results are usually worth the effort.
What is HDR Photography Anyway?
Whole books have been written about the technical and mathematical aspects of high dynamic range imaging; however it doesn’t have to be that complicated. Before we start, let’s take a step back and talk about what HDR photography is.
Light is measured in exposure values (EV). An EV can be thought of as a stop, but it also includes the shutter speed and focal length. Imagine standing in a dimly lit room and looking out a window toward a sun filled sky. Our eyes can clearly discern objects in the room and the delicate details of bright clouds in the sky outside. This is because the human eye can perceive approximately 15-25 EVs of light and adjust to nearly any other range of light outside that in just a few moments.
Unfortunately modern day camera sensors simply can’t record the same range of light. To compensate, photographers combine multiple exposure of a scene to extend the perceived range of light. This can be done using special programs or manually through careful compositing.
Creating an HDR Image Using Compositing Techniques
Since the middle of the nineteenth century, creative photographers have been extending the dynamic range of their photographs by combining multiple negatives into positive composites. We are going to do the same thing except we will be using Photoshop.
The EV or range of light in the image above was simply too great to capture details in the dark areas of the old building and the bright clouds overhead in a single shot. To extend the perceived dynamic range of the image, I manually combined two separate photographs of the scene in Photoshop. One image was exposed for the sky and the other for the building.
My first step was to setup my camera on a tripod. Although it’s possible to combine multiple hand-held images, it’s much easier and more precise to use a tripod. Once I was happy with the composition, I set the exposure and captured four images approximately one stop apart.
I could have merged all four of these images in Photomatix or some other HDR program; however I chose to manually combine two of the images in Photoshop to shape how the final image looked.
In the image below, I exposed for the beautiful, dark details of the building and let the bright values (in the sky) blow out.
The second image I used captured the delicate details of the clouds. Although the sky looks great, many of details around the building have been clip and are completely black. Don’t you love how dramatic the clouds look though?
The compositing process started in Adobe Camera Raw. I made color correction adjustments and then opened each image in Photoshop.
Creating a Composite
The first step is to overlay the darker image (with crisp detail of the clouds) onto the brighter image. To do this, I selected the Move tool (shortcut “V”) and moved the first image on top of the other while holding down the Shift key. Holding the Shift key ensures that the image you’re moving is centered. Next I made a rectangular selection below the skyline and hit the Delete key to remove everything below it.
I attached a white layer mask to the top image layer and painted with black the areas I wanted to hide. Think of a layer mask as sitting on top of the layer it’s attached to. In this case, the white layer mask is covering to the second image layer.
The rule of thumb with layer masks is that completely black hides the layer (next to it) while white reveals it. Layer masks can be used to create a transition between two images.
To create a layer mask, select the top layer and then go to Layer -> Layer Mask -> Reveal All. I made a precise selection around the building and used a black, fuzzy paint brush to create a natural transition between the ground and sky.
Note: Be sure that you have the layer mask (not the layer) selected when you begin painting!
The composite is a little rough, but it’s starting to take shape.
Removing Dust and Increasing Contrast
The next step was to clone out sensor dust in the sky. I then created a Curves Adjustment Layer to pump up the contrast. I made a very gentle “S” curve and then used my previous Layer Mask and applied it only to the sky. You can copy a Layer Mask to another layer while holding the Alt/Option key and dragging the mask to the new layer. In this case, I copied my original Layer Mask to the Curves Adjustment Layer.
Reducing the Color and Enhancing the Mood
I came up with this next technique with while playing around in Photoshop many years ago. This two-step process reduces vibrancy and adds a dark edge. The first step is to create a Channel Mixer layer and tick the Monochrome box. This dumps all the color. Next pump up the Reds to +40, Greens to +40 and Blues to +20.
The second step brings back some of the color. Select the first four layers in the group by pressing the Alt/Option keys while clicking on each layer. This includes the original Background layer, the second “Sky Enhance” layer, the “Remove Dust” layer and the Curves adjustment layer.
With all four layers selected, press the following keys together: Alt/Shift + Ctrl/Cmd + Shift + E. I know this sounds a tiny bit complicated, but it’s really not. This is a shortcut to merge all of the selected layers into a single merged copy and stack it at the top of the group. Now change the Blending Mode of this new layer to “Overlay” and reduce the Opacity to 65%. This two-step process creates a dark, vintage-like effect.
Note: You can change the Blending Mode of any layer by clicking the drop down menu (usually set to “Normal”) near the top of the layer panel window. The Opacity slider can be found right next to the Blending Mode menu.
Applying a High Pass Filter to the Foreground
I wanted to add some crispness to the wheat in the foreground so I applied a High Pass filter to it. I began by creating another merged copy of all the layers. This time I selected all of the layers in the group and pressed the Alt/Shift + Ctrl/Cmd + Shift + E keys. I applied a High Pass filter to this new layer by clicking Filter -> Other -> High Pass. In the High Pass popup box, I set the Radius to 10.0 Pixels and clicked Ok. I changed the Blending Mode to Overlay and reduced the Opacity to around 50%.
The High Pass filter can wreak havoc on an image if you’re not careful. Not only did I reduce the filter by 50%, I also masked it out so that it only affected the grass.
Dodging and Burning
We’re almost done! Overall, I am happy with how the image looks, but it can be refined even further. I used the Dodge and Burn tools to selectively lighten and darken portions of the image. Careful use of these tools can give your image a more three-dimensional look.
To setup a Dodge and Burn layer, hold the Alt/Option key while clicking on the “Create a New Layer” icon at the bottom of the layers panel. This will open up a popup box. Rename the layer, change the Blending Mode to Overlay, tick the Fill with Overlay-neutral color (50% grey) box and click OK. Now we are ready to start dodging and burning.
The dodge and burn tools are located on the left side of the Photoshop workspace. Click on either tool and then look for the Range and Exposure settings at the top of the screen.
The Range setting allows you to decide what pixels should be affected by the dodging and burning. For example I often select Highlights with a Range of 7 or 8% for the Exposure to lighten vegetation. For darkening clouds I select the Burn tool and change the Range to Shadows. To lighten or darken an entire range of pixels, select Midtones for the Range.
Adjusting the Range properly is a matter of personal taste and takes a bit of practice. I almost never go above 10% with the Exposure. Instead I slowly build up the effect.
It takes a little bit of practice with the tools to get a feel for how they work.
Try changing the brush hardness to see how it changes things. You can adjust your brush size and hardness by right clicking anywhere in the image and moving the sliders back and forth. Try to avoid increasing the exposure too quickly. You can build up the effect you’re trying to achieve by repeatedly clicking in the area you are working with your mouse.
I dodged (lightened) some of the details around the truck and house and burned (darkened) the roof and grass to enhance details.
We’re done! It took a bit of effort to accomplish, but the final image has a dark, edgy feel that can’t be easily duplicated with an HDR program.
Image compositing is just one approach to HDR photography. These processing techniques can be applied to a wide variety of situations. While the process of merging images together seamlessly can be frustrating at first, it’s usually well worth the time and effort. I invite you to download the original layered image and experiment with the adjustment layers. Have fun!
Download the Exercise File Here!
HDR Processing Walk-Thorugh Using Photomatix
HDR Software Comparison
Bloch, C. (2007). The HDRI Handbook. Rocky Nook.
Howard, J. (2010). Practical HDRI, 2nd Edition. Rocky Nook.
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