Making Sense of HDR with Harold Davis
by Jim Cornfield
HDR Imaging at work in a bridal study. Automated HDR software and Photoshop technique combine to save the delicate highlight and shadow details that give this portrait its painterly charm.
September 05, 2012 —
Most photographers know that the current buzzword in the world of digital imaging is HDR—High Dynamic Range. It describes a process for maintaining detail throughout the entire tonal range of an image, from the darkest areas to the lightest. Today it’s accomplished digitally by merging several versions of the same photograph. But, despite the technology that makes this possible, the core concept of HDR imaging is one of photography’s oldest ideas. Many refugees from the wet photography era remember spending hours at the enlarger, under the glow of a safelight, coaxing detail out of the shadows and highlights of a single frame. Now, the digital universe has commandeered HDR as the queen of its after-capture applications. YouTube, blogs and websites sizzle with HDR tutorials, and the book publishing business has gone into overdrive. I recently counted 40 HDR titles on Amazon.com alone (and there were more; I just stopped counting).
A lot of HDR literature seems (admirably) skewed toward the idea of restraint when using this tool—in order to avoid that artificial “in your face” look that exposes the heavy hand of the person at the mouse and keyboard. Naturally, there are times when creativity demands taking HDR’s capabilities beyond the realm of simply balancing highlight and shadow values. The instinct for knowing when it’s okay to cross the line isn’t necessarily hard-wired into most of us; Harold Davis is an exception. His newly released 192-page Creating HDR Photos (Amphoto Books) is a meticulously detailed HDR tutorial. It’s also a guide to discovering the moments when taking more creative license with HDR might be appropriate. Davis is an interesting hybrid of fastidious technologist (he’s a mathematician and former software developer), and a widely respected, award-winning creative artist; parts of his book dissect the elaborate workflow he taps for his own best-known imagery. Fortunately, Creating HDR Photos is masterfully organized to acquaint even beginners (I confess to being one of them myself) with this fascinating subset of our craft.
The image shown below demonstrates a common application of HDR: balancing brightness levels in the sky, the middle ground and foreground of a landscape shot. In this case by merging images in the Layers Palette of Adobe Photoshop. The subject is California’s Owens Valley. “As I looked out at the sunset before me,” Davis writes, “I felt my eyes automatically adjusting to the immense tonal range of lights and darks.” A single shot would be incapable of reproducing the entire dynamic range that the human eye can detect in this scene. With his camera secured to a tripod, ISO set to 100, and aperture at f/22, Davis made six exposures, varying each by one EV using exposure times from 1/13 sec. up to 1.6 seconds [image above]. Shutter speed bracketing (rather than f-stop brackets), ensures that exposure changes will affect only brightness levels, and not depth-of-field. Back in his digital darkroom, Davis used Photoshop’s layer palette, the gradient tool and masking, as shown in the illustrations, in order to, in his words, “selectively add the three differently lit portions of this image: the brightly lit mountains...the valley...and the edge of the volcanic upland in the right foreground”. The combined layer stack was then flattened to create the final image. The Photoshop command is Layers > Flatten Image, a process Davis likes to call “smooshing.” Hand-HDR is obviously best accomplished by someone with well-tuned Photoshop skills. Fortunately, there are now some less labor-intensive options, variations of automated software that greatly simplify the process. These include an HDR Pro function built into current versions of Photoshop itself.
Nik HDR Efex Pro
This popular software (www.niksoftware.com) can be installed as a standalone HDR program, but runs easily as a Photoshop plug-in. A recent upgrade, HDR Efex Pro 2, has several new features, but with either version, you access the Nik dialog box in Photoshop via the File>Automate command. With this particular sequence from Creating HDR Photos, Davis demonstrates the ease of using Nik products, and, more importantly, the careful pairing of that distinctively “HDR look” with an appropriate subject. This abandoned frontier home [top] in the ghost town of Bodie, California, writes Davis, “was full of rich textures—the scene cried out for HDR.” With camera on tripod, Davis made six exposures [as shown in sequence in 10, left] at ISO 200 and f/9. using shutter speeds from 2.5 sec. to 1/60 sec. The images were then downloaded to a desktop folder, and the pictures selected via the Nik interface dialog box [2nd image]. After a brief wait, a quite passable HDR image appeared in the main Efex Pro window beside a vertical row of “presets.” These are variations from which to choose an adjusted version of the final image. That selection can be further manipulated using the sliders on the window’s right side. For this image, Davis chose a preset labeled “Realistic (Strong),” and then modified colors, contrast and brightness to suit his vision for the finished piece—in this case a painterly tableau, suggestive of an Edward Hopper painting—distinctively HDR in style, but appropriate for rendering this slice of bygone Americana.
Early in Creating HDR Photos, Davis summarizes his picks for subjects that are “clear winners” as candidates for HDR processing: “Anything with wide dynamic range, from lights to darks; landscapes, particularly when the foreground is in shadow, and the background is bright (or vice versa); architectural photography, particularly when the subject combines interiors and exteriors; interiors of rooms with light coming in windows or skylights; glass, glassware, reflections and mirrors; anything with details and textures that can be dramatically enhanced; metal, metallic surfaces, and machinery.”
The most versatile ingredients for working with these subjects are the RAW file and Adobe Photoshop, ideally version CS5 or later. Davis describes an array of techniques for combining these powerful tools to create HDR images, all with limitless variations and “tweaking” potential. The defining moment of the HDR process is to first produce multiple versions of a single photograph, spanning exposure values (EV’s) from under- to overexposure. There are two ways to accomplish this: in-camera exposure bracketing (a series of shots that encompass the metered exposure plus images at least two stops under- and two stops overexposed); secondly, there’s “multi-RAW” processing of a single image in which a series of exposure variations is processed from that picture’s RAW file. These two work modes form the foundation of Harold Davis’ lessons in the craft of HDR.
Nik HDR Efex Pro: Multi-RAW Variation
HDR lends an interesting dimension to portraits, but bracketing a series of shots isn’t always practical in a typical portrait session, where subjects are prone to movement, however slight, between exposures. Fast burst firing and auto bracketing can help, and automatic HDR software features an alignment function to bring the component images into register in a finished picture. But even this approach is not totally reliable. Since a single RAW file contains eight EV’s worth of exposure latitude, Multi-RAW processing of one image is the best option for gathering a full dynamic range series for an HDR portrait. Davis chose HDR for this particular study [13, above] to emphasize the subject’s rugged skin texture, and to open up the shadow areas where the large shoulder tattoo and the man’s off-camera eye were lurking in the original exposure. The tattoos represent his children’s faces, and Davis wanted “to emphasize the gritty masculine nature of this man and to [contrast] his external toughness with his tenderness for his kids.”
The picture was shot handheld at 1/160 sec., f/8, ISO 100. Three versions of the image—normal, -2 EV and +2 EV—were processed from the file using Adobe Camera Raw, a Photoshop plug-in that permits re-processing of a single RAW file. The results were combined in Nik HDR Efex Pro [14, on pg. 51] and a black-and-white version was selected from the presets menu. The surprising touch of color in the eyes was simply added to the finished shot with the Selective Color function in Photoshop.
The earliest version of automated HDR software, Photomatix (http://photomatix-pro.en.softonic.com) is also available as a standalone program or Photoshop plug-in. This series, processed in Photomatix, is distinctive for the simple approach it demonstrates, using HDR to remedy a universal problem we all encounter in outdoor photography . No single exposure is capable of doing justice to this interesting combination of rock textures—one is practically obscured in shadow and the other background element in bright sunlight. Here, Davis has chosen to show us that not all HDR solutions require RAW files. The three bracketed exposures are, in fact, JPG files, made according to the one EV separation scheme—4/5 sec. , 1/6 sec. , and 1/80 sec. . Davis acknowledges that, despite the great flexibility that RAW files allow in after capture manipulation, the lowly JPG, sufficiently bracketed for processing in automated HDR software, can yield a perfectly satisfactory end product. Once the shots are downloaded and Photomatix Pro is launched, the workflow and onscreen tools are similar to Nik Efex Pro and Photoshop HDR Pro. The finished image speaks for itself. Even if you’re still among the “digitally-challenged,” or one of the skeptics who still place HDR somewhere between a dark art and a parlor trick, it’s almost unthinkable that you’ve never encountered the pervasive photographic problem shown in this last scenario. If the result of this rudimentary HDR application hasn’t sold you, I suspect nothing will.
A Hands-On HDR Lesson
On a blustery afternoon, Harold Davis took me to the Marin Headlands overlooking San Francisco Bay to practice a little of what I’d learned of HDR imaging. The subject was one of his favorites: the familiar Golden Gate Bridge (Wilderness Press published his book on the topic, 100 Views of the Golden Gate, in 2008).
As Davis tramped effortlessly over steep, shrub-lined trails, we settled on a vantage of the bridge’s north tower and the entire span across to the city. The idea was to combine a building’s details, as revealed by late afternoon light. The effect is always a bit surreal, but it produces an approximation of what the human eye is capable of seeing at dusk. The bridge offered a perfect opportunity to do something similar, but with the latitude provided by automated HDR software—in this case, Nik HDR Efex Pro 2. Photos 1, 2 and 3 show a few of the bracketed component shots I needed, as they appear in my Canon’s Viewer Utility software. The vignetting in this series is an unintentional artifact. I needed the wide focal length, and planned to crop the final image in after-capture. If I’d wanted to maintain the full crop of my in-camera exposure, Nik and other software provide functions for correcting vignetted corners. The camera was mounted on a solid gitzo tripod, and, with the winds rising on our exposed camera position, I further secured the pod to a sturdy wooden post. To get the detail I needed in the foreground of the final shot, I processed one of the images (Picture 4) in Adobe Camera RAW, around 4 EV’s up from the normal exposure. The shrubbery in this area was cleaned up in the finished image using Photoshop tools, before saving it as a TIFF file.
Back in my studio, with a multiple image HDR situation under my belt, I put Nik HDR Efex Pro 2 through its paces in the Multi-RAW processing mode. A good contender was a candid portrait I’d done of a little girl a couple of years ago in the backcountry of mainland Honduras. The inset photo to the left reveals it as a quick shot, with extremely contrasty lighting. I wanted to emphasize the rugged life of a child living in a shack at the edge of the mangrove forest. The wooden wall texture could help that, and HDR was a good tool for highlighting that feature. With no reflector, or strobe, the shadow side of the girl’s face could use some opening up, and that too was an easy Efex Pro 2 task. In Adobe Camera RAW, I processed three variations of the original camera exposure, one EV under and +1 and +2 EV over. Nik Software did its magic, and yielded a set of preset variations. I selected the one that, for me, came closest in color and texture rendition to telling the story. I saved it as PSD file, tweaked the color a bit more in Photoshop and finished it off as a TIFF.
Writer/photographer Jim Cornfield, based in Malibu Canyon, CA, is a regular contributor to Rangefinder.
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