When To Find Gap And Glow Light
Finding both gap and glow photos is a matter of luck, but there are ways to improve your odds. The first is to arrive early and stay late. The best glows often peak 15 to 30 minutes before sunrise or after sunset, then fade. I try to arrive at my shooting location 45 minutes to an hour before sunrise so I have time to dress warmly and set up. There's very little time between the beginning of civil twilight, when it becomes light enough to see without a headlamp, and the moment of peak light, so it's important to scout the location the day before, when you have ample time to find the perfect foreground and dial in the best possible composition.
Squall Light In Black-And-White
Storm light over the Cimarrons, Uncompahgre National Forest, Colorado.
There's a third category of rare light that's particularly interesting in black-and-white. Fred Picker, founder of Zone VI Studios and a noted large-format black-and-white shooter, dubbed it "squall light." Here's how Picker described squall light in his newsletter in 1985: "A black bright presence that arrives in a rush to announce heavy rain or high wind or a cold front coming through. Squall light, though rare, seems more frequent on summer evenings but it can appear, where I live, at any time of the year. Its effect is startling. Dark objects seem bright, somehow concentrated, as though charged with energy. Pale objects radiate light. The effect is unearthly, unsettling, exciting, surreal."
Picker doesn't attempt to analyze the atmospheric optics of what he observed, so I can't offer a scientific explanation. His description intrigued me, however, so I searched back through my files for color images that seemed to fit his description. I selected two, which I call "Storm Light over the Cimarrons" and "Stormy Sunrise Over Windom and Sunlight Peaks," then converted them to black-and-white using Lightroom's Develop Module.
Both images exhibit what I call the "spotlight effect," where the sun finds a momentary gap in heavy storm clouds and shines a beam of direct sun on a portion of the subject, leaving the rest of the scene shrouded in dense shadow. The contrast between the spotlit region and the dark surroundings intensifies the apparent brightness of the spotlit subject. That contrast also creates a challenge for in-camera meters used in evaluative or matrix meter mode. If the spotlit region is small, your meter may ignore it and recommend an exposure that renders the shadowed regions as a midtone. That, in turn, can overexpose the spotlit region. If you have time, spot-meter the spotlit region and open up about one stop; if you feel pressured, bracket your exposures, then check the histogram to make sure the darkest frame has excellent highlight detail.
A second way to improve your odds is persistence. Both kinds of photos depend on the presence of clouds, of course. It's one of the paradoxes of landscape photography that widespread clouds increase the risk of getting skunked and increase the chances of getting a very good photo, if you get one at all. It's awfully tempting to poke your head out of your tent or bedroom window, see clouds blotting out the stars and go back to sleep. Don't succumb. Sooner or later, you'll miss a great shot. Whenever I get tempted to hit the snooze button (which is almost every time I shoot), I remind myself of the first rule for chasing great light—the potential reward is always greatest when the odds against you are the longest.
You can see more of Glenn Randall's work, sign up for his monthly newsletter, read his blog and learn about upcoming workshops at www.glennrandall.com.