Lighting Video at Night
Shooting at night can be the most difficult problem for digital video filmmakers, except for filming under water. At night you have the awkward position of filming something that is both visible and looks as though it is actually at night. Often times you will have sources of light in your environment, such as lights from a building or even a little bit of moonlight, but this is not always going to be true. The process of actually making your night image, which is filmed at night, appear correct is called night for night.
All the images you see in a nighttime environment come from specific sources. These could be actual light bulbs or from the moon, but either way they usually come from a fixed light location. To achieve night for night you have to set up your lighting pattern with this in mind.
Every light source has to be identifiable in a sense, or at least traceable back to a probable location when put under inspection. This means that they have to come from reasonable angles and locations. Light through windows, moonlight coming straight from above, and passing car lights are all possible ideas. At the same time the lights have to be very sharp, produce strong shadows, and have very fast falloff.
Just as with day for night you can use a series of gels and filters in night for night to correct the effect. At times you will have to use a blue filter to help the moonlight appear correct, and slight yellow filters are often used for streetlights. At night colors have less contrast and you will notice that all colors should be less intense.
Try a few desaturating filters to work on this, and make sure that any light color there is does not have too much color saturation. For example, if the gel you are using for the moonlight has too intense of a blue tint then you may have to lose it or color balance the final image.
Night for night is best when there is a little bit of natural light to use. The dark hours of dusk and twilight are great because you will get enough light to see the general areas, but not enough for it to look like day at all. If this is the case you must be well rehearsed ahead of time because you will usually have less than an hour to film.