THE BLUE HOUR
By Alan R. Lichtenstein
The Blue Hour is the time of day when the sky takes on an inky blue/purple hue. It’s not really an hour, but in general it is the time from about 40 to 10 minutes before sunrise and from 10 to 40 minutes aftersunset. These averages vary depending on latitude as well as the season. There are several sub-sets of the blue hour, The Pure Blue Hour, the Classic Blue Hour, and the Hybrid Blue Hour, each with its own characteristics, and while the techniques for photographing images are relatively similar, each differs somewhat in the techniques used to photographic scenes during those times.
THE PURE BLUE HOUR
The pure blue hour requires that the sun be a decent way below the horizon. It generally occurs between 40-20 minutes before sunrise and between 20-40 minutes after sunset. It is characterized by the deep blue color that is present when the sky is turning from blackness to daylight before sunrise or the last gasp of blue just before darkness when the sky has the last remnant of light before retreating to the black of night. I term this the pure blue hour, because the only thing present is the pureness of the blue color.
THE CLASSIC BLUE HOUR
The classic blue hour is broken up by a central light source, usually incandescent. The focus of the light adds contrast to the blue.
HYBRID BLUE HOUR
I have found that you can combine the dying sunset or the emerging sunrise colors with the blue hour and although such images are technically not either sunrise/sunsets or blue hour, the combination of these two times can give striking images. These are what I term hybrid blue hour images because they combine the onset of the blue hour with the either the emerging colors of the sunrise or the dying colors of the sunsets. Here’s the subject in the first image taken just before the sun has fallen below the horizon when there is still some color left.
Hybrid Blue Hour images can be enhanced by the presence of clouds. Although these are not always available, if you get them, they make striking images.
CREATING IMAGES DURING THE BLUE HOUR
THE CONVENTIONAL WISDOM
The Blue Hour is simply a special case of low-light photography, with an emphasis on the blue/purple hues of the sky. Conventional wisdom for Blue Hour photography is pretty much the same as it is for low-light photography: Use a tripod, ISO set to between 100-200 and manual focus. This is because the dark of the Blue Hour may render autofocus (AF) systems inoperable and manual focus is desired. It is suggested that you check the focus using live view, although you may focus using the viewfinder. Using manual exposure settings, set the aperture for maximum depth of field (usually the higher f-stop number), and a shutter speed between 5-30 seconds. Depending on your camera and how fast your lens is, you might have to experiment to find the correct shutter speed. If you have trouble assigning these numbers, you can set to manual focus and set your camera to Program mode, set your ISO as described above and let the camera select a combination of aperture and shutter speed to match the conditions. Meter using either spot or center-weighted average.
If you don’t have a tripod, you can use an alternative method and handhold the camera. Set all your functions to AUTO, select your metering option as above. But here you’re going to have to compensate. I generally find an EV of between -.3 to -1.7 works best. The slight. Underexposing of the image tends to enhance the color while creating the sense that the time of day was still night, but rapidly fading towards daylight. Not compensating will reduce the effect of the Blue Hour making your pictures lighter than you would want. This is a deficiency you’ll find if you try to use your phone to take these images. You’re phone just can’t give you the necessary compensation you will need. Whichever method you use. Blue hour photography is exciting and well worth it.
Hybrid Blue Hour images pose another problem; white balance. In regular blue hour images, the color is. mostly that blue/inky purple color, but in hybrid images you have a great range of colors, whose Kelvin temperatures range as much as 5,000o. AUTO white balance just won’t do. Here, I recommend the following:
- Set your camera’ mode to P (Program) and let the camera select the ISO, aperture, and shutter speed.
- Meter your camera to either center-weighted average or spot, depending on the scenery.
- Measure the white balance by using either an EXO disc or actually measuring the amount with the LIGHT METER app.
- Next, adjust the white balance setting to enhance the color you want enhanced. This will primarily be the blue, so you are going to set your white balance lower than your measured amount. I suggest you start out by lowering the white balance by between 750oK and 1000oK. What you’re doing is telling the camera that there is an overabundance of red/orange in the scene, so the camera will emphasize the blue hues.
- Compensate between -.3 EV and -1.7 EV. If you have a mirrorless camera, you can usually see the results of the compensated image in the viewfinder so you can see which compensation works best for the scene.
Blue Hour Photography challenges the skill, but the images you get are noteworthy: