Those 3 Words We Love to Hear, Day for Night (DFN). What better three words could a director ask to hear? No huge generators, no freezing temperatures, no vampire-style living... what's not to love?
Are you perplexed? Well, long ago, back in the days of black-and-white film (yes, both black-and-white and film), way back then, directors didn't have the equipment or the money to light up large outdoor scenes, so they devised a way to trick the audience by shooting night scenes during the day. Those old directors loved a rather simple technique of darkening the scene and changing the contrast, and eventually the color. I bet that, after following these few easy tips, you will fall in love with it too.
First, never shoot the sky. The sky is completely dark at night and light during the day. In order to achieve the effect and trick your audience, you must not see the sky. Pick your backgrounds carefully, and move in closer. Maybe a heavily-wooded area or a city alleyway might work. Any place the sky is covered or not visible works best. If you must see the sky, your only option is to use filters. A graduated neutral density (ND) filter, used in conjunction with a composition consisting of a strong horizontal line, like a skyline or horizon, can help sell the effect. Position the filter so it just touches that horizontal line to hide the edge of the graduation. However, beware: you won't want your subject to cross into the bottom of the graduation, because it will call attention to the filter, as well as just darken the subject's head. Bad - very bad.
Dim the Light
In order to sell the night, you need to raise the contrast. You can achieve this two ways. The first is by darkening down your image and lowering your light level by two stops. Notice I said darken down, not iris down. Sure you can iris down, but, as you may already know, higher f-stops mean sharper focus (aka long depth of field), and we all know how much we love the opposite of that. So, if you like soft backgrounds and shorter depth of field, try using a standard ND filter (preferably an ND6 or ND9). This will give you a darker image without sacrificing your soft backgrounds. Now doesn't that make your heart skip a beat?
Light a Candle
Ambiance is as important to romance as it is to DFN. By adding nocturnal elements to your image, you add believability. Now, lighting candles would add ambiance under normal circumstances, but for this effect you will need more power. Remember, you're competing with the sun. Try having your talent carry a strong flashlight or turn on the high beams of cars in the shot. These light "gags," as they are called in the industry, help sell the shot.
Audio is important, too. Have you ever been out at midnight and heard hundreds of cars whizzing by or tons of people walking around? No. No one is up at midnight - well, except crickets and hoot owls. Find a quiet area or make the area quiet. Then add in natural sounds of the night. You'll be amazed what a little audio sweetening will do.
Watch the Sunset
If your scene is relatively short, there is one other trick you might try, and that is waiting for twilight. Twilight is the short amount of time between the sun setting and total darkness, usually lasting about 20 minutes or so. By waiting for this time, you lose the sun in your sky and still maintain a considerable amount of ambient light. This is the time you can really use practical lights in your scene. Try turning on lights in the windows of homes or turning on signs of businesses in the background. If you can arrange it, you might even try having the street lights turned on early. Can you feel it yet?
Keep Your Cool
The final and probably the most important stage of this effect is to cool down the color temperature of your camera. Most people believe that blue light represents moonlight, and, while sunlight is considered to have blue tint due to its cool color temperature (5600 - 6300 degrees Kelvin compared to a tungsten desk lamp at 3200 degrees Kelvin or a fire which might be 1800 degrees Kelvin), moonlight is much bluer. So let's add a blue filter, right? Wrong. Blue filters are usually off the scale of color temp, and we are trying to trick our audience, not point out the elephant in the room. Try white balancing your camera on something warmer than white. If you have CTO (color temperature orange) gels that you use on your lights, put them in front of the lens, and then white balance on white. If your camera has the ability to adjust the color temperature manually, try moving it into the 6000 degree Kelvin or higher range, essentially tricking your camera.
If it is still not blue enough, you can also gain some more blue by moving the shot into deep shade or shoot during an overcast day when the color temperatures are very high. This will further widen the gap between a slightly tungsten-balanced camera and the blue color temps of the outdoors, thereby creating even more blue. Remember, "If night is where you want to be, blue is what you want to see."
Keep It Simple, Stupid. The whole concept of shooting Day for Night is to take something that is generally hard and make it easy. By keeping your shots simple and adhering to the tips I've provided, you will be making moonlight magic before you know it.
Michael Reff is Director of Photography at Turner Broadcasting.