Posted on June 23, 2019
Several people in this month’s New Zealand workshop had stated pretty emphatically that the Milky Way was a prime reason for attending—one guy even said his wife had told him not to come home without a Milky Way picture (we think she was joking). So no pressure. I reassured everyone in the orientation that I had multiple Milky Way shoots planned, but as the workshop’s nights ticked off, each Milky Way plan was doused—first by clouds, later by moonlight. And with the moon brightening and closer in the sky to the Milky Way each night, the we’d about run out of time.
I’d known all along that a waxing moon meant that our best Milky Way chances would come in the first half of the workshop. And I’d decided long before the workshop started that our final night would be especially problematic for the Milky Way not just because of the moon, but because of our location. But desperate times call for desperate measures, so with just a couple of days to go, I decided to recheck my calculations for about the millionth time (maybe a slight exaggeration, but you get the point). The two nights in Twizel were out of the question—the moon would be pretty much in the Milky Way. But our last night, in Queenstown…. Hmmm, maybe, just maybe, we’d have a 30-45 minute window between sunset and moonrise when the sky might be dark enough for the Milky Way to shine.
But the moon wasn’t the only obstacle. The forecast called for “high clouds,” a frustratingly vague forecast. And even if the sky darkened enough and the clouds cleared, we were in Queenstown, where I’d long ago decided that city lights and the orientation of Lake Wakatipu made finding Milky Way vantage point with a dark enough sky (no light pollution) and a nice enough foreground (lake and mountains) impossible. The moonlight and clouds risk were irrelevant if I couldn’t find a Milky Way location. But I had to give it a shot. Zooming in on the map, my eyes landed on one small tiny of lakeshore with enough of a twist that might work, though I’d never photographed there or even considered its Milky Way potential. But that was enough for me to circle the date and location and tell the group that we were going to give the Milky Way one more shot. All that was left to do was monitor the forecast and wait.
Wanting to be certain (and to avoid hunting blindly in the dark), on the way to our final sunset shoot I asked the driver to swing by my potential spot. I was relieved to confirm that the angle was good, and that there was an open, easily accessible stretch of beach. Yay. Down the road at our sunset location I just watched the clouds and hoped. The sky seemed clear enough there, but looked a little less promising back in the direction of my Milky Way location.
Arriving in twilight I hopped out of the van and checked the twilight sky—In addition to the promised high clouds, an accumulation of thicker clouds sat on the horizon more or less where the brightest part of the galactic center would be. And there were indeed a few high clouds, but Jupiter’s appearance was a relief because I knew Jupiter was on the leading edge of the Milky Way that night. Waiting for darkness, I prepared the group and just tried to stay positive. Every few minutes I’d return to my camera and fire a test frame to see if the sky was dark enough and look for any hint of moonlight.
You can’t imagine my excitement the first time my LCD displayed the faint glow of the Milky Way angling above 6000 foot Cecil Peak—we were in business. As the sky darkened, the Milky Way unfurled overhead in all its Southern Hemisphere glory, flanked by Jupiter and thousands of other stars in completely unfamiliar arrangements.
I started with my dedicated night photography setup, my Sony a7SII body and Sony 24 f/1.4 GM lens, trying a variety of horizontal and vertical compositions. After about 15 minutes I switched to my Sony 16-35 f/2.8 GM, sacrificing two stops of light for a wider field of view (more Milky Way). I liked the extra sky and stuck with that lens for the rest of the shoot.
After about 30 minutes of happy shooting we started to detect a brightening that signaled the moon’s approach behind The Remarkables (my hands-down favorite mountain range name). But rather than being a show stopper, the moonlight added a diaphanous sheen to the previously dark clouds and we kept going. As we wound down, the entire group was giddy with excitement, and I was giddy with relief. Just as we were started to pack up, I detected the faint reflection of Cecil Peak on the lake’s surface and adjusted my composition to include it.
To say that this night exceeded my expectations would be an understatement. In fact, my expectations almost dashed the entire shoot. It was a good a reminder not to get too locked in to preconceived notions. Had I stuck with my original belief that our final night in Queenstown wouldn’t work, I’d never have found a great Milky Way location—and one of the best shoots of an already great workshop would never have happened.
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Posted on June 16, 2019
What a crazy life this is. Last month I was rafting the Grand Canyon in short pants and flip-flops, this month I’m bouncing around the New Zealand countryside in my warmest wool and down. Between timezone shock and temperature whiplash, my body isn’t quite sure whether it’s coming or going, but the relentless beauty down here seems to transcend all that difficulty enough to keep me going.
Mirror Lakes is a must-stop on the road to Milford Sound in Fiordland National Park. It’s a popular stop even in mid-winter, but with the help of our New Zealand-based driver, Don Smith and I have figured out how to thread the needle between the tour buses originating in nearby Te Anau, and the tour buses originating in distant Queenstown, and still make it just before the morning sun reaches the water and washes out the reflection.
When our van pulled up here on Friday morning, I was surprised to see a large tour bus right out front, but Steve (our driver) said don’t worry, they’ll be loading up any second—sure enough, within five minutes we had this gorgeous view to ourselves with at least 45 minutes of shade remaining on the water. As pretty as the scene is, limited views through the surrounding foliage make it a little tricky to photograph, so I’m usually content to stand back and let the group work with the prime photography real estate. But on this morning chilly morning last week, I found the clouds and reflection so irresistible that I went looking for a way to photograph the scene without getting in anyone’s way.
I soon found myself over in one the far corner of the most popular railed viewing deck, a zone where the patient (and not-so-patient) wait behind thick overhanging branches for better views to open up. My first thought as I eyed the scene was how cool the branches look—too bad they block the view. But then I realized that by lowering my camera almost all the way to the deck, I could completely eliminate the most dense set of branches at the very top of the frame, and use the lower branches as diagonal compositional elements—without blocking the snowy peaks, or their reflection.
The problem with this idea was the vertical bars in the deck’s protective railing, which appeared too closely spaced to fit my lens through. But just for laughs I pulled the lens out anyway and tested its width against the bars. Sure enough, every opening was too narrow—well, every opening except one. For some reason, the gap separating one, and only one, pair of bars was about an inch wider than all the others, making a gap just wide enough to slip my lens through.
The technical part of the scene was pretty straightforward, though potentially quite awkward with my camera about eight inches off the ground (it’s not the getting down to ground level that’s a problem, it’s the getting up). These are the very situations where I’ve grown to love the articulating LCD on my Sony a7RIII. In this case I was able to compose, level, focus, and meter from the (relative) comfort of my knees.
After centering Mt. Eglinton, I focused on the branches knowing that at f/16 and 18mm, I’d be sharp all the way to infinity. The dynamic range was pretty extreme, but my histogram told me that it was workable if I was careful. With all that out of the way, the biggest problem remaining was the ducks that insisted on swimming through the reflection—fortunately, I’m nothing if not patient (stubborn), and was able to out-wait them long enough to click this frame.
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Posted on November 5, 2018
One evening in New Zealand
I get to a lot of locations and see so many spectacular sights that they sometimes run together. But every once in a while I experience a shoot I know I’ll never forget.
One of (many) highlights of the New Zealand workshop is the hike to Tasman Lake in Aoraki / Mt. Cook National Park. The reward for this short, steep (335 stairs) hike is a 270 degree view that includes 12,000 foot Mt. Cook, icebergs drifting atop turquoise Tasman Lake, Nun’s Veil (pictured here), and the Tasman Valley.
At the trailhead most of the workshop group decided the trail was too icy and opted for a beautiful but less treacherous view a couple miles back down the road. As Don led them to the alternate spot, I guided four members who wanted to brave the icy trail. It turns out the ice wasn’t a big problem, and in fact was completely gone from the trail within a couple hundred yards, and we made it to the vista short of breath but otherwise unscathed.
I’d been up here a few times, but it was the first time for the others, so it was fun to watch their reaction as they summited. Because the trail ends here and the viewing platform is fairly compact, we were able to work in close proximity all evening—having others to share our awe with enhanced the experience even more.
The Tasman Lake view is one of those vistas that’s far too broad to capture with a single frame; any attempt to do so shrinks every feature to the point of insignificance. Opting to divide and conquer by identifying and isolating the scene’s most compelling features, my eye instantly landed on the reflection of Nun’s Veil’s in a small pool down the slope. I soon hopped the vista’s small retaining wall to better center the reflection in the pool, then spent much of the evening here working on compositions that included the reflection. My clicking intensified as light on Nun’s Veil warmed, coloring the wind-whipped snow encircling the peak.
As if all that wasn’t enough, a few minutes after the light left Nun’s Veil, a full moon appeared just to the right of the peak. Despite the advancing night, we were able to photograph the moonrise for a few minutes before the scene became too dark to capture detail in the foreground and moon. But even facing a walk down the icy trail in the dark, we lingered in the moonlight just to marvel at the majesty. As we donned our headlamps for the walk back down the trail, I heard one of the members of the group call my name. “Gary,” long pause. “That didn’t suck.”
Who doesn’t love the soothing tranquility of a good reflection? And like a metaphor in writing, a reflection is an indirect representation that can be more powerful than its literal double by virtue of its ability to engage the brain in different ways than we’re accustomed. Rather than processing the scene directly, we first must mentally reassemble the reflection’s reverse world, and in the process perhaps see the scene a little differently.
Reflections are a powerful photographic tool as well. Water’s universal familiarity makes it an ideal subject for photographers frustrated by their camera’s static representation of our dynamic world. Just as we freeze or blur a waterfall to express turbulent motion, we can include a reflection to convey serenity.
Water reflections come in many forms, from a mirror-sharp reverse of a mountain atop a still pool, to an abstract shuffle of color and texture on a choppy lake. Without getting too far into the physics of light, it’s important to understand that every object we see and photograph (that doesn’t generate its own light) comes to us courtesy of reflected light.
Mirror reflection recipe
The ingredients for a crisp, mirror reflection like the El Capitan image at the top of the page is pretty simple: still water, a reflection subject that’s much brighter than the water’s surface (the greater the contrast the better), and a view angle that matches the angle from the water’s surface to the reflection subject. (The best reflections are usually found on shaded water because there are fewer photons to compete with the photons bouncing from the reflected subject.)
The El Capitan reflection above was a perfect confluence of reflection conditions. Clean, still air, dense shade on the river, and El Capitan’s fully exposed, reflective granite, make early morning the best time for El Capitan reflections. On this April morning I made my way down to the Merced River hoping to photograph the first light on El Capitan reflected in the Merced River. Finding my route down to the river blocked by spring flooding, I was forced to improvise. The morning air was clean and calm, and the ephemeral lake was mirror-still.
Circling the flooded meadow, I found a gap in the trees that opened onto the most complete view and reflection of El Capitan and the Three Brothers I’ve ever seen. So complete in fact, that I couldn’t include it all with my 16-35mm lens at its widest focal length. Fortunately, I was able to borrow a Canon 11-24 lens and Metabones IV adapter from a friend (thanks, Curt!), just wide enough to fit the entire scene at the lens’s shortest focal length.
Playing the angles
Understanding that reflected photons leave the water’s surface at the same angle at which they arrive—imagine the way a tennis ball bounces (if it weren’t affected by spin, wind resistance, or gravity)—helps us get in position for the reflection we want.
A few years ago I found myself atop Sentinel Dome right after an intense rain shower had turned indentations in the granite into small, glistening pools. Rather than simply settle for the vivid sunset coloring the clouds above, I decided to include the sunset reflected in the pools as well. At eye-level the pools reflected blue sky, so I dropped my tripod as low as it would go, almost to granite level, positioning my lens at the same angle to the pools that the red light leaving the clouds struck the water.
When the water’s in motion
As spectacular as a crisp, mirror reflection in still water is, it’s easy to overlook the visual potential in a reflection that’s not crisp, or to forget your camera’s ability to render a soft or abstract reflection much better than your eyes view it. While a crisp reflection often dominates the primary subject in an image, a splash of reflected color or shape can provide a striking accent to a dominant primary subject. And a reflection disturbed by the continuously varying angles of rippled or choppy water magically appears when a long exposure smoothes the water’s surface.
In the image on the right, the El Capitan reflection undulating atop the Merced River was barely perceptible to my eyes. But the reflection came to in a 25 second exposure achieved with the help of 2-stop hard graduated neutral density filter that subdued the day’s last rays on the clouds and El Capitan, and a neutral polarizer (with the reflection dialed up) that cut the light on the entire scene by a couple of stops. And since a reflection is never as bright as the actual scene, using a GND meant I need to do a little dodging and burning in Photoshop.
Where to focus
An often misunderstood aspect of reflection photography is where to focus. Though it seems counterintuitive, the focus point of a reflection is the reflection subject, not the reflection surface. This isn’t such a big deal in a scene like the El Capitan reflection at the top of the post, where the focus point of everything of visual significance is infinity, but it’s a very big deal when you want both your reflection and rocks or leaves on the nearby water surface sharp.
The El Capitan reflection on the right is very different from the El Capitan reflection above, where the extreme depth of field ensured sharpness had I focused on anything in the scene or the reflection. But here the leaves that were my scene’s primary emphasis were just a couple of feet from my camera, while El Capitan was several thousand feet distant. Even though the leaves floated atop the El Capitan reflection, focusing on El Capitan would have softened the leaves. To increase my depth of field, I stopped down to f/18 and focused several feet into the foreground leaves, then magnified the image on my LCD to verify that all of the leaves were sharp. Though El Capitan is slightly soft, a soft reflection is far more forgivable than a soft fore
It seems that reflections often feel like a fortuitous gift that we just stumbled upon. But given that reflections are entirely beholden to the laws of physics, they’re far more predictable than many of the natural elements we photograph. Taking a little time to understand the nature of reflections, and how they’re revealed by a camera, enables photographers to anticipate their appearance.
For example, in Yosemite I know that low flow makes autumn the best time for reflections in the Merced River. On the other hand, when the Merced is rushing with spring runoff, Yosemite’s meadows often shimmer beneath tranquil vernal pools. I plan many trips (and workshops) to take advantage of these opportunities.
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Posted on October 28, 2018
One summer when I was a kid my family took a camping vacation to the Canadian Rockies. Bits and pieces of that trip return to me as vague memories, but one memory permanently etched in my brain is the color of Lake Louise and Moraine Lake. My dad, a very passionate amateur photographer, was frothing with excitement and must have gone through half his film budget (remember those days?) at Moraine Lake alone. Nevertheless, and despite my dad’s pictures, I couldn’t fully process a world where water could be that color and for many years after that doubted my memory.
Long before visiting New Zealand I accepted that water really can be that color, but still had few opportunities to view it. Then I started visiting New Zealand, where photographing the lakes and rivers gives me a little déjà vu—it’s just plain disorienting to see water this color.
So what’s going on?
In areas of persistent cold, snow can accumulate faster than it melts. Over many years of accumulating, the snow’s weight compresses it into ice and a glacier is born. A glacier is incredibly heavy; since pressure decreases the freezing point of ice, at the interface between the glacier and the underlying rock (where the pressure of the ice’s weight is greatest), melting ice lubricates the glacier and allows it to move downhill. The glacier’s extreme weight combined with this forward motion breaks up the rock. Embedded with these rock fragments, the glacier behaves like sandpaper, grinding the rock on which it slides into finer and finer particles. The finest of these particles is called “glacial flour.”
Meltwater from the glacier flows downhill, carrying scoured rock with it. While the larger rock particles simply sink, the glacial flour remains suspended in the runoff. While most of the sunlight striking water infused with glacial flour is absorbed by the suspended particles, the green and blue wavelengths aren’t absorbed; instead they scatter back to our eyes and we are treated to turquoise water. The water’s exact hue (whether it appears more green or blue) is determined by the size of the suspended particles, which dictates the relative amount of green and blue wavelengths they scatter.
About this image
The Hooker Valley track is a spectacular 3-mile hike beneath Mt. Cook to Hooker Lake. This gradually sloped trail follows the Hooker River’s twisting turquoise ribbon, snaking back and forth across the water on three swinging suspension bridges. It doesn’t take too much time on the trail to understand why this is one of the most popular hikes in New Zealand.
This year’s workshop group didn’t have time to do the entire 6-mile roundtrip, but since the beauty starts pretty much in the first 100 yards and doesn’t let up, we guided them up the track with instructions to take their time and photograph without concern for how far they got. It turns out most only made it to the first bridge, initially stopped by the view of the river and mountains, and then by the sunset that colored the clouds above the peaks.
This image came from fairly early in our bridge shoot, when clouds capped the scene and I took advantage of the soft light to stretch my exposure and smooth the water. Here I was a few yards up the trail from the bridge, which allowed me to make the river a diagonal stripe across the frame. Less than thrilled with the fairly boring foreground shrubs, I moved around a bit until I found a large rock to occupy the that part of the frame.
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Posted on September 9, 2018
One of the questions I get the most about the New Zealand workshop Don Smith and I do is, “Why winter?” The simple answer is that it’s the best time to photograph there. This answer is usually followed with, “But isn’t it cold?” Not really—it’s more like a Northern California or Oregon winter, with highs in the 40s and 50s, and lows in the 20s and 30s. Also like Northern California and Oregon, New Zealand’s South Island gets some rain and fog in the lowlands, and snow in the mountains—so much better for photography than the persistent blue skies of the California summer I left behind.
While the conditions are certainly tolerable, and winter storms whiten the many peaks and fill the skies with interesting clouds, when pressed for more specifics on my preference for a New Zealand winter, it’s usually not long before I get to the night sky. With clean air and minimal light pollution, New Zealand is an astrophotographer’s paradise any season. But winter is when the Milky Way’s brilliant center shines prominently all night, rising much higher above the horizon than my Northern Hemisphere eyes are accustomed to.
One night in Wanaka Don and I took the group for short drive out to a vista overlooking Lake Hawea, one of many large glacial lakes decorating the South Island. I knew we’d get the Milky Way, but had forgotten about Mars, near opposition and shining brighter than it has in 15 years. We found it rising across the lake, so bright that it cast a sparkling reflection on the water. I started with vertical compositions, but soon switched to horizontal to include both Mars and the snow-capped peaks rising above the north shore.
Here are a couple of links to help with your night photography:
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Posted on August 5, 2018
Virtually every scene I approach with a camera is beautiful, but a beautiful scene is rarely enough for a great image. Human experience of the world differs greatly from what the camera captures—the photographer’s job is to understand and use those differences.
I’ve always felt that viewers of an image are more comfortable exploring the frame—and therefore tend to linger longer with the image—when they have a starting and return place. So the first thing I do when trying to turn a beautiful scene into a beautiful picture is create that place by finding something to anchor my frame. Sometimes this anchor is an object that’s beautiful in its own right (such as a reflection, a flower, or the moon), but often it’s just a grounding element that aligns with the scene’s more striking features.
When I approached this scene on the shore of Lake Pukaki in New Zealand, I was struck first by the rich glacial turquoise water (I’ve seen a few lakes with similar color, but none that were nearly as big as Lake Pukaki), and second by the snowcapped peaks lining the distant shore. And in the pre-sunrise gloaming I could see that the sky was very nice too—maybe not spectacular, but with lots of character in the clouds plus the potential for soft, warm light when the sun finally arrived. Given all the scene had going for it, I probably could have raised my camera and composed something decent from any spot with a view of the lake, but a scene like this deserves something more than decent.
So before advancing any further, I performed my standard scan for something to anchor my frame, a visual element to surround with the scene’s inherent beauty. I was instantly drawn to an area of the beach where a few rocks protruded from the lake and quickly made my way down to the water. At the shore, in addition to the rocks that drew me I found a striking mosaic of rocks submerged beneath the clear water. A bonus for sure, but as beautiful as these submerged rocks were, as I tried to get all the visual pieces to fit together I quickly realized that they introduced a layer of complication as well.
For the next 10 or 15 minutes I wandered the lakeshore experimenting with compositions that used a variety of foreground rock combinations, but couldn’t really find anything that thrilled me. I’d click a frame or two, evaluate the result, but just couldn’t seem to organize all the foreground rocks with the mountains and sky to form something coherent.
But this wasn’t the time to become discouraged. I knew something was here and continued experimenting, hoping to find it before the light changed. As the sky brightened, I settled on the trio of rocks you see in this image. They aligned nicely with the mountains, better than anything else I’d found so far. But they were also orbited by a disorganized arrangement of satellite rocks that competed with the simple foreground I sought. I moved closer, extending my tripod as far into the water as I could, then dropped low and composed a fairly tight frame.
Eliminating the superfluous rocks made my foreground all about the rock trio, and with a few tweaks (preliminary frames followed by adjustments) arrived at the composition you see here. At this point the rocks were just a few feet from my camera, making depth of field a concern. Assisted by my hyperfocal app, I stopped down to f/18 and focused at the back of the farthest rock, taking only a couple of frames before I was confident my hyperfocal distance was dialed in.
The final piece of the puzzle was dealing with the chop in the water. Sometimes water motion can be a feature and I try to find a middle ground that softens it while retaining a bit of shape or texture. In this case I wanted simplicity, and felt that anything that wasn’t mountains, rocks, or color would be a distraction. The solution was to smooth the water as much as possible with a 15-second shutter speed.
There’s nothing inherently special about the rocks I used to anchor this image. The scene’s true beauty lies in the water and mountains, but if I’d have settled for an image that was just water and mountains, there would have been nowhere for your eye to land. Adding a simple foreground element to anchor my frame serves as a visual launching pad from which you’re free to explore the rest of this beautiful scene.
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Posted on July 24, 2018
We’ve all heard it: “That’s so fake,” or “You Photoshopped that,” or some other derisive barb implying that an image is trying to be something it isn’t. But before you say that about this image, let me say that I processed it five times, each time dialing down the saturation, attempting to create something that would appear credible to the dubious masses. And with each pass, the color looked a little less like what we saw this unforgettable New Zealand morning. So finally I just said, enough is enough—you’ll just have trust me when I tell you that for the sake of credibility, you’re already being cheated of that morning’s full spectacle.
Don Smith and I got our New Zealand winter workshop group up early to photograph sunrise at the famous Wanaka willow tree. The tree was just a short walk from our hotel, and even though we still had 45 minutes until sunrise, it was apparent the second we stepped outside that something special was in store. Though it was still dark enough to require flashlights, already the entire sky radiated a rich ruby red. Since we’d shown the group the tree the prior afternoon, a few rushed ahead, but Don and I held back with the stragglers. Nevertheless, even the stragglers pace quickened as the red deepened, and by the time we reached the tree we were pretty much jogging.
Turns out we needn’t have rushed. For the next 30 minutes the red intensified until everything in sight seemed to buzz with color. I’ve experienced color like this a few times in my life, and the best way to describe is that it feels like the light possesses a physical component that penetrates my skin and everything else it touches. And with the sky throbbing in all directions, I felt like I might get dizzy whirling about to avoid missing something. Soon we all just started laughing at how unbelievable the show was, knowing that every picture we shared would be met with the obligatory “That’s so fake” skepticism.
All this got me thinking again about what causes color in the sky, so I dusted off a post I wrote a few years ago, tweaked a few things, and…
A sunset myth
If your goal is a colorful sunset/sunrise and you have to choose between pristine or polluted air, which would you choose? If you said clean air, you’re in the minority. You’re also right. But despite some pretty obvious evidence to the contrary, it seems that the myth that a colorful sunset requires lots of particles in the air persists. If particles in the air were necessary for sunset color, Los Angeles would be known for its incredible sunsets and Hawaii would only be known for its beaches.
But what is the secret to a great sunrise or sunset? Granted, a cool breeze, warm surf, and a Mai Tai are a great start, but I’m thinking more photographically than recreationally (sorry). I look for a mix of sky (to pass the sunlight) and clouds (to catch the color), with a particular emphasis on a clear horizon in the direction of the sun. But even with a nice mix of clouds and sky, sometimes the color fizzles. Often the missing ingredient, contrary to common belief, is clean air, the cleaner the better. And like most things, it all makes sense when you understand what’s going on.
Light and color
Understanding sunset color starts with understanding how sunlight and the atmosphere interact to make the sky blue. As you probably know, visible light reaches our eyes in waves of varying length, with each wavelength perceived as a different color. Starting with the shortest wavelengths and moving toward the longest, visible light goes from violet, indigo, blue, green, yellow, orange, and red. (These color names are arbitrary labels we’ve assigned to the colors we perceive at various points along the visible portion of the electromagnetic spectrum—there are an infinite number of colors in between each of these colors.) When a beam of light passes through a vacuum (such as space), it moves in a straight line, without interference, so all its wavelengths reach our eyes simultaneously and we perceive the light as white.
Why is the sky blue?
When light interacts with a foreign object—for example, when a beam of sunlight enters our atmosphere—different wavelengths respond differently depending on the size of the molecules they encounter. If sunlight encounters molecules that are larger than its wavelengths, such as atmospheric impurities like dust or smoke, all of the wavelengths bounce off (reflect). Because these large molecules are of varying sizes, a variety of wavelengths (colors) get blended into a murky sky with a gray or brown cast. If all the wavelengths get bounced equally, the sky will appear white(ish).
When a beam of sunlight hits the much smaller molecules of the gases that comprise our atmosphere (such as nitrogen and oxygen), some of its wavelengths are absorbed while others are reflected and scattered in all directions. Because the shorter wavelengths (violet and blue) scatter most easily; the longer wavelengths (orange and red) continue on to color the sky of someone farther away. The more direct the sunlight’s path to our eyes, the less atmosphere it passes through and the more we see the first (blue) wavelengths to scatter. When the sun is high in our sky, its light takes the most direct path through the atmosphere and our sky is most blue (assuming no pollutants have altered the scattering). In the mountains, sunlight has passed through even less atmosphere and the sky appears even more blue than it does at sea level.
When the sun is on the horizon, the light that reaches us has traveled through so much atmosphere that at the very least it has been stripped of its blueness because the blue wavelengths are the first to scatter (those wavelengths are coloring the sky of someone whose sun is high overhead). And if that sunrise/sunset light hasn’t encountered larger dust and smoke molecules on its journey, only the red wavelengths will have survived unscathed, and everyone enjoys the show.
The cleaner the air, the more vivid the sunrise/sunset color. To understand the mixing effect that happens when a variety of wavelengths are bounced around by large airborne particles, think about blending a smoothie consisting of a variety of brightly colored ingredients (such as strawberries, blueberries, and spinach—yum). Your smoothie’s color won’t be nearly as vivid as any of its ingredients, not even close. Instead you’ll end up with a brownish or grayish muck that might at best be slightly tinted with the color of the predominant ingredient. That’s what happens to the color when the light has to interact with large airborne particles like dust, smoke, and smog. Because these particles aren’t of uniform size, they each reflect a slightly different color rather than allowing one vivid color to dominate. In the middle of the day pollution means less blue; at sunrise/sunset, it’s less pink, red, and orange.
Clouds can enhance sunrise/sunset color by catching the red wavelengths and reflecting them back to our eyes, but only if there’s an opening on the horizon for the light pass through. Without clouds, the red wavelengths continue on to color the horizon opposite the sun—a “twilight wedge” when the color is in the sky, and “alpenglow” when mountains jut into the colored region of the sky and take on the color themselves.
So. To the skeptics who reflexively dismiss pictures like this, you might want to suggest that they spend more time out in nature. Whether it’s a tropical bird, a fluttering butterfly, a field of wildflowers, or a New Zealand sunrise, there really is nothing subtle about color in nature.