The term blue hour, derived from “La hora azul” in Spanish, or “L’Heure Bleue” in French, is a period of time just before the appearance of the rising sun or right after it sets. Blue hour is most commonly known for its romantic connotations and the stunning visual quality it brings to dramatic scenes in films and photography.
It’s the moment when the sky has a predominantly deep blue hue and the light is soft enough to emphasise the most of the dark areas of the scene, without requiring any additional light source. This is due to Rayleigh scattering, which is the scattering of light by particles smaller than the wavelength of visible light, the same process that makes the sky blue.
When the sun reaches six degrees below the horizon, it is no longer directly illuminating the ground, but it is illuminating the upper atmosphere. This is known as civil twilight. During this period of time, red light, which has a longer wavelength than blue light, passes through the atmosphere into space, while the blue light gets scattered and diffused.
In the morning, blue hour occurs just before golden hour at the beginning of civil twilight, which is around 30 minutes before the sun rises. In the evening, it occurs at the end of the civil twilight, just after the golden hour and starts roughly 10 to 15 minutes after the sun has set.
POPULAR SUBJECTS YOU CAN CAPTURE
Blue hour photography is an easy genre to master as you usually do not have to worry about harsh lighting or shadows in your shots. Landscapes, cityscapes, and portraits are photography genres that work very well during blue hour as the soft overcast light can create an ethereal mood in your scenes.
GUIDE TO PHOTOGRAPHING DURING BLUE HOUR
If you are new to blue hour photography, here are some tips to help you get started:
• As blue hour depends on your geographical location, remember to check the time of your local sunrise and sunset.
• Plan ahead and get to your location early. You will need to give yourself enough time to set up your gear.
• Mount your camera on a tripod for stability and compose your image with the skyline as the backdrop.
• Keep your ISO as low as you can to lessen the grain and noise in your image.
• During blue hour, you will need to use a slower shutter speed for your images to be properly exposed. Shoot in shutter-priority or manual mode as these allow you to manually select your shutter speed.
• To achieve a sharp image, use a remote or turn your camera’s timer on. Pressing the shutter release button can sometimes cause unintentional camera shake, resulting in a blurry shot.
• Take some test shots and always check your histogram to ensure you have no overblown highlights or unnecessary shadows.
If you are using a DSLR to capture your shots, try experimenting with High Dynamic Range (HDR) photography. An HDR image comprises of a number of shots taken at different exposure levels, which are then blended together during post-processing.
Some Nikon DSLRs have a built-in HDR mode feature, where multiple exposures of a scene are captured and combined in-camera to form an HDR photograph.