Cinematography : Doing Day-For-Night by Jethro Randell

During filming you're at the mercy of the sun. You don't want a partly cloudy day with clouds moving across the sun. So go with the sun, or go with overcast (great big diffuser). Harsh sun means actors will be squinting, and then there's shadows. Sunlight gives you harsh shadows and high contrast. Cloudy/overcast gives you diffused light and low contrast. In post, color correction, you'll reduce your contrast, reduce your exposure, and desaturate your colors a bit. Toss a light vignette on it (optional).

Is there a reason you're trying to shoot during the day instead of at night? I'm assuming there is a wide shot involved?

Also, I found this recent video on DFN filming: https://www.youtube.com/watch?v=l0AyCAQaxnU

Yeah, quite a few wide shots. Want to explore that option as it would be better for budget and scheduling to do it in the day time. If I can incorporate it into the style and give it a good look, think it'll be a win-win. Also thanks for the link, will look into filters too

Day for night is workable, but there are a number of pitfalls that end up being problematic. With the software we have available it is easy to replace the sky (try to avoid shooting the sky if you can to cut down the VFX) bring the exposure down, and tweak the color. Problem is the discrepancy between what you see in your imagination and what others see when you present that on screen. Much of the day for night and night work I’ve seen in the past while are frankly unwatchable. Literally, unwatchable. Can’t see anything. Make it dark, blue, and replace the sky. A formula that guarantees bland flat hard to see images that take the audience out of the story.

Forests vary, depending upon the density of growth, height of trees and the layers. For a successful day for night I always find that it is important to have highlights so that you as least get some shaping and depth in objects. Some sunlight dappled on parts of the background goes a long way toward bringing texture and something to silhouette people against. An audience trying to see what is happening and who is talking will quickly turn on you. That same sunlight must be kept as a backlight on performers while the contrast on their faces can be adjusted with either lighting instruments of reflectors. Knowing what your camera sees and the lighting ratios you need to achieve what you want might take a little experimentation, but once you know what you need a few light readings and you should be good to go and consistent in your lighting ratios and exposure. Costumes need to be given careful consideration.

As so much of the image will be dark, it is really import that the camera you use has very little noise in the blacks. If not, then you will have to crush the blacks to eliminate the range of exposure in the toe that will be noisy. I can think of cameras that I would need to crush the blacks by 3-4 stops for the image to be acceptable. You need to know. TEST. If you are unsure of exactly what you wish to do, give yourself some leeway. The most adjustable image will be a normally exposed one, but critical to the day for night effect will be that nothing is overexposed including highlights. You can look at establishing the degree of underexposure that gives you your desired look in camera, but that will lock in your images more than shooting a normal exposure then applying the effect in post. If you are unsure, then making the adjustments on post is a good idea in this one situation. Same goes for the color you use. Moonlight is the same color temperature as sunlight since it it the sun reflecting off of a pretty neutral grey surface. How many solidly blue night scenes have we all seen? When lighting a night scene, I find that layering colour as well as light and shadow works well. You will not have that luxury. The layering of light and shadow is somewhat doable if you shoot on a sunlit day and choose your locations and shooting times so that you have shadows you can use.

One other thing to think of is that for any artificial light to look real, be it a flashlight, house light, fire or a match it will have to be really bright because of the ambient daylight you are actually shooting in will be quite high. Remember that sunlight is around 10,000fc and more so any lights have to be very bright. I recently watched a series where all the night scenes were day for night. Decently done but those scenes with flashlights ruined the illusion.

I cannot stress this enough, test everything to establish your look and shooting methodology.