|High-contrast, backlit images like this are excellent candidates for HDR treatment, but it's easy to go overboard. Glenn Randall's final image shows proper restraint, creating a rich image with good dynamic range.|
We've all heard the sales pitch: High-dynamic-range imaging has solved photography's last great problem, creating beautiful, realistic photographs of high-contrast scenes. In many situations, no single capture can record the full range of tones we can see with our eyes. By making a bracketed series of exposures and combining them in suitable software, photographers can, at last, make images that truly match what they saw.
Do you buy it? Many of my students don't. They're intrigued by HDR's potential, but dissatisfied with the unnatural-looking results and put off by the hassle and complexity (not to mention cost) of learning new software.
Imagine an approach to HDR imaging that's inexpensive, uses software you may already own and know, is completely nondestructive, and produces the most natural-looking results I've seen. Sound like I'm selling snake oil? I'm not.
The solution is to use Lightroom. You get to use all the familiar Lightroom tools to edit your HDR image in exactly the same way you'd edit any single RAW file. All of your edits are nondestructive, which means you can change your mind and re-edit the same file as many times as you like. Editing an image in Lightroom doesn't change the underlying pixels. Instead, it changes the instruction set that Lightroom applies to those pixels when you export the image as a JPEG for the web or a TIFF for printing. That instruction set can be changed at anytime. Lightroom is moderately priced, and it has many uses beyond editing HDR images. Best of all, the results are usually better than I've gotten using Photomatix Pro 5, HDR Efex Pro 2 or HDR Expose 3. In this case, the easiest way is also the best way.
There are a couple of small catches. First, you must use Lightroom 4.1 or higher. Earlier versions can't tone-map (the technical term for edit) 32-bit files. To understand the second catch, you need to know a bit more about how HDR imaging works.
The process starts with a bracketed set of images, preferably shot on a tripod, that are identical except for the exposure. I usually shoot a five-frame bracket set with a one-stop bracket interval, so my exposures range from two stops under the meter's recommendation (-2 exposure compensation) to two stops over (+2 exposure compensation). The next step is combining all of those images into a 32-bit, high-dynamic-range TIFF, which brings us to the second catch. Lightroom 5.3, the latest version as I write, can't create 32-bit files from your bracketed set of images. You must use additional software to create that 32-bit file.
There's a simple fix, fortunately. Create the 32-bit file using Photoshop CS5 or higher, Photomatix Pro or Merge to 32-bit HDR, a $29 plug-in for Lightroom created by HDRsoft, the same company that makes Photomatix.
1) Maintain good local contrast in the highlights and shadows to preserve a realistic look.
2) Clarity is a great way to add life to areas that might otherwise appear flat, but don't overdo it. A setting between 10 and 30 is usually sufficient. Remember that you can paint on Clarity with the Adjustment Brush to confine the effect to only those areas that need it.
The easiest solution is the Merge to 32-bit HDR plug-in, available at www.hdrsoft.com. After installing the plug-in, simply select all the images in Lightroom, right-click, and then choose Export > Merge to 32-bit HDR. In the next dialog box, I always check Reduce Noise. I check Remove Ghosts if some part of the subject, such as branches or flowers, may have moved in between frames. Check Align Images if you were shooting handheld or on a shaky tripod. After you click Merge, the 32-bit tiff is returned to Lightroom automatically.
If you already have Photomatix Pro, you don't need the plug-in. Just launch Photomatix Pro as a stand-alone application (don't access it through Lightroom). Click on Load Bracketed Photos. In the next dialog, check the box labeled Show 32-bit Unprocessed Image. Choose your preprocessing options, which are similar to those in the Merge to 32-bit HDR plug-in, and click Merge. If you chose Show Options to Remove Ghosts, you'll get the option to draw a selection around the ghosted area. You then can choose one frame from your bracketed set that Photomatix will use to create the image within the ghosted region. This is a more effective deghosting technique than is available through the plug-in. You can also choose an automated method of deghosting. If nothing was moving when you shot your bracketed set, leave this box unchecked. Once the merge is complete, choose File > Save As. Select Floating Point TIFF as the file format and click OK. You can close Photomatix, since you'll be using Lightroom to complete the tone-mapping procedure. Import the saved TIFF file into Lightroom. If you've put the file in the same folder as the source images, as I usually do, then you can just right-click on the folder name in the Library panel and click Synchronize Folder. Be sure to check Show Import Dialog Before Importing. When that dialog opens, uncheck any Develop presets you may have created and click Synchronize.
It's easy to go too far with HDR, especially when you try to bring up shadow detail. Let your shadows be shadows and resist the temptation to over-enhance. You want the final image to feel real.
If necessary, you can create the 32-bit tiff in Photoshop, but I don't recommend it if your image contains the sun. In my experience, the resulting file often shows odd, nearly impossible-to-correct banding in the sky, whereas the file created in the Merge to 32-bit HDR plug-in or Photomatix will show no such artifacts. For the record, here's the procedure in Photoshop.
First, go into Lightroom's Preferences (Edit > Preferences) and choose External Editing. In the File Format drop-down menu, choose TIFF. PSD files won't work for this procedure. In Lightroom, select all the images in your bracketed set and choose Photo > Edit In > Merge to HDR Pro in Photoshop. When the Merge to HDR Pro dialog box opens, choose 32 Bit in the Mode drop-down menu. All editing options will disappear. The image will look terrible. Don't worry, just click OK, and Photoshop will create the 32-bit file. Again, it may look awful. Save the image. There's no need to change the file name or location. It will appear in your Lightroom catalog right next to the original RAW files.
Tone-Mapping 32-Bit TIFFs In Lightroom
Regardless of the method you use to create the 32-bit file, the next step is the same: Open the image in Lightroom's Develop module. The first thing you'll notice is that the Exposure slider now shows a +/-10-stop range instead of the usual five. While you'll probably never use the full range of the slider, the magnitude of possible adjustments shows just how broad a range of light intensities is contained in a 32-bit file. I usually start by using the Exposure slider to adjust the overall "feel" of the image, the overall balance of lights and darks, without worrying too much initially if that adjustment pushes either end of the tonal scale off the chart. Most often, 32-bit tiffs come in feeling "heavy," with excessively dark shadows, so I start by opening those shadows with the Exposure slider.
1) Let highlights be highlights. Allowing bright areas of the image to become near-white enhances realism.
2) Keep textural contrast enhancements under control. Creating an undesirable "grunge" look screams "HDR."
3) Let shadows be shadows. Retaining small areas of pure black increases the dynamic range of the image and makes highlights appear brighter by comparison.
Moving on to the Shadows and Highlights sliders, I try moderate moves first. Values over 50 for the Shadows slider can flatten shadow contrast, creating an unnatural look. Strong moves of the Highlights slider are less likely to cause problems. Remember that leaving a little bit of pure black and almost-pure white in your image enhances realism. The light tones will look lighter when placed next to pure black, enhancing the image's apparent dynamic range. Most high-contrast scenes have some element that should be placed as high in the tonal scale as possible without clipping the element to pure white. The disc of the sun itself is an exception; it will always be blank white. The need to retain small areas of pure black and near-white is the main reason you should be cautious with the Blacks and Whites sliders. I like to set Lightroom's background color (Edit > Preferences > Interface) to white so I have a visual reference for highlight brightness. Keep an eye on the histogram as you make adjustments. It's your best guide to what's happening in the image.
Many 32-bit images will benefit from adding contrast in the Tone Curve panel. That added snap in the midtones can make the image more lively, but also darken the shadows and brighten the highlights excessively. Rather than returning to the Shadows and Highlights sliders, consider adjusting shadow and highlight density with the Graduated Filter and Adjustment Brush, which tend to preserve believable local contrast within the highlight and shadow regions better than strong moves of the Shadows and Highlights sliders.
HDRsoft's Merge to 32-bit plug-in does tend to enhance saturation. If your image has become garish, consider dialing saturation down by 5 or 10 points.
Using the Lightroom approach to HDR will let you recover much more clean, usable detail, even in the darkest shadows and brightest highlights, than you can from a RAW file. This approach comes closer than any method I've tried to achieving the goal of creating evocative, lifelike renderings of the high-contrast scenes that often yield the best landscape images.
You can see more of Glenn Randall's work, sign up for his monthly newsletter, read his blog, and learn about upcoming workshops at his website, www.glennrandall.com.