How to make a camera night filter?

We're making a movie, and we want to make it appear like it's night time, but we are filming during the day. How would we make a cheap filter for over the camera lens to make it appear to be night. Thank you.

We're making a movie, and we want to make it appear like it's night time, but we are filming during the day. How would we make a cheap filter for over the camera lens to make it appear to be night. Thank you.

*edit* This would be in color.

Day for night shooting was (is) done by underexposing the film about three to four stops. In motion picture photography, depth of field is important in most situations, so just stopping the lens down three to four stops won't usually cut it.

ND filters can be stacked until the right t/stop (transmission stops are usually marked on most motion picture lenses) can be used in the scene.

COLOR OR B&W ???

If you're going with black and white, you need to use a red filter on a cloudless day. With a dark enough red filter, you'll get a jet black sky, however the clouds will really stand out. For that reason, if you're going to use this technique, you'll need to only work on a cloudless day or digitally remove the clouds.

I don't know of any way to do this with color other than really shooting at night.

What if you used a very strong ND (neutral density) filter on the camera, and used a LOT of lighting for your subjects?