February 10, 2011

Beyond Sunset: The Different Phases of Twilight

Photographer James Brandon explores the magical world of twilight that begins after the sun has disappeared beneath the horizon.
Sunsets are one of the most common and widely photographed events in nature. They are stunning and inspiring to watch and never seem to last quite long enough before everything is over. I’ve been on quite a few photo walks with groups of photographers during sunset, and I always notice the same thing: Once the sun dips below the horizon, the majority of people pack up their gear and head home. They see a setting sun as the end of a wonderful night of shooting, but they are missing so much!
I see the same thing with portrait photographers. I can’t tell you how many times I’ve been out shooting a lifestyle or engagement session at a popular location during sunset and watched all the photographers scramble to get their shots in. Sure enough, as soon as the sun sets the place clears out, which is fine by me!
What most photographers don’t understand is that once the sun has disappeared, a new window of opportunity begins, there is still plenty of useable light left! Twilight is the period of time in between day and night, and is caused by refraction and the suns rays scattering from the atmosphere. What most people don’t know is that there are three different phases of twilight, each with very distinct and unique features that open up different worlds of opportunities for your images. My goal for this article is to shed some light (pun definitely intended) on what happens after the sun goes down, and to let photographers know that the setting sun is just the beginning!

Sunset and Sunrise
The period of time leading up to sunset or directly after sunset are the most popular times for photographers. The light is beautiful and perfect for portraits and landscapes. The sunlight is diffused and less harsh, and beautiful warm tones are cast across the horizon. Sunsets and sunrises are also popular photographic opportunities because the sun acts as another interesting element in a photograph because of it’s low relative position to the horizon, which can’t be done during the day time in most cases. I think there is also something very spiritual about these times of day, they have a way of making people stop and take everything in. It’s both calming and invigorating. But all across the world, at all the sunset watching parties and photo walks, as soon as the sun hits the horizon people begin to pack up and head home. Little do they know that twilight is upon them and the many photo ops of the evening have just begun.

Civil Twilight
Civil twilight is the brightest phase of twilight and occurs from the moment the sun dips below the horizon and lasts until the center of the sun is geometrically 6 degrees below the horizon (or from the time the sun is 6 degrees below the horizon until it hits the horizon in the morning). This period of time lasts about 30 minutes on average but can be longer or shorter depending on the time of year and your position on the globe. During civil twilight, you may also be able to see the brightest stars in the sky, as well as some planets like venus. The horizon is clearly visible and taking handheld pictures is relatively easy to do. Objects are clearly defined and no additional light is needed in most cases. The light cast during this phase can be anywhere from warm golden tones to cool pink tones.
During civil twilight, the colors of the sky are going to be changing quickly. The sunset colors are going to go away and an entire new set of colors are going to splay out across the sky. These colors are going to become cooler in temperature as time goes on and it’s important to be able to adapt to the quickly changing conditions. As the next phase of twilight approaches, the gradation from the sunset point to the other end of the sky is going to become very smooth and pleasant, and the dynamic range of light in your images is going to decrease drastically.

Nautical Twilight
Nautical twilight occurs right after civil twilight in the evening, and right before civil twilight in the morning. This phase occurs when the center of the sun is between 6 and 12 degrees below the horizon in the evening. This period also usually lasts around 30 minutes and the primary color cast across the atmosphere is usually a deep blue tone with still noticeable orange and yellow hues left over from the fading sun. The horizon is still visible during this time but hand held shots are going to be somewhat difficult by now. The light has started to dissipate quickly and silhouettes are going to be more prevelent in your shots. Details will be harder to make out during this time but there is still some remaining light on the horizon from the sun.
This is a great time to start looking for artificial light for your images. During nautical twilight, the artificial lights in buildings and structures will really begin to take over the scene, and there are endless opportunities for compelling images. Be sure to use a tripod during this time as hand held images will be extremely difficult. Pay attention to the way the remaining light and manmade light in your scene interacts with the subjects in your image. Use the directional light from the horizon to add hints of definition to objects and be ready to take multiple images as the light conditions will change rapidly.


Astronomical Twilight
The last phase of twilight is known as astronomical twilight, or “astro” for short. This period of twilight occurs when the center of the sun is between 12 and 18 degrees below the horizon and slowly degrades over a period of 30 minutes before night time officially begins. Getting hand held images during this time is pretty much impossible, and a tripod is strongly suggested. During this phase of twilight, there is still some useable light to make for very interesting pictures but night will be approaching quickly.
Cityscapes really comes to life during this time and the smallest light becomes a powerful tool of illumination. There is still a faint cast of dark blue across the horizon at first, and this slowly turns to black as night time begins. Away from the city, stars will be very visible and can be incorporated into some shots. Details will be somewhat difficult to make out without the help of some sort of artificial help. This phase of twilight is certainly the most difficult for creating images, but it can still be very rewarding.


Read more: http://www.digital-photography-school.com/beyond-sunset-the-differen-phases-of-twilight#ixzz1DY7kkSFB

Sunset and Sunrise

Nautical Twilight

Astronomical Twilight

© Jacob Lucas
Civil Twilight

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