Get ready for one of those “They don’t teach you this in film school!” posts! Mention a green screen in film school and you’ll get some chuckles. “We’ll fix it in post!” and “What are we shooting? ‘The Life of Pie’?” are some of the reactions I’ve noted from my old peers at film school whenever the topic of green screens come up. Like it or not, however, green screens dominate the world of corporate video. Whether it’s out of unimaginativeness or lack of budget corporations love green screens and in order to excel in the world of corporate video production you have to excel with green screens. From either lack of foresight or openness, my professors in film school didn’t think to teach me the basics of green screens. Regrettably, one of my most successful videos ever with over 34,000 views showcased my first ever foray into green screen production. However, since then I’ve learned a lot of tricks that you can use to boost the production quality of your green screen videos.
Lighting
When it comes to green screen work, the most important step in the process is the lighting! You can get all other aspects of a green screen shoot right but, if you fail in the lighting department you’re in for long hard hours in your editing bay. If you take one thing from this post it’ll be that you have to light the subject and green screen separately! It is imperative that you light the green screen as evenly as possible to get a tight key. It helps to use Kino Flo type lamps on either side of the green screen. If you have a fancy studio with rigging on the celling, that helps too! If you’re on a budget I’ve seen people rig shop lights vertically to achieve flat lighting too. If you do use shop lights, make sure you use high quality, high CRI bulbs/LEDs for good quality results. Regarding your subject, keep it simple with 3-point lighting. I’ve seen a lot of discussion about what color temperature to use. One highly skilled digital effects artist recommends daylight for your subject and tungsten for your green screen, however I’ve had enough success using daylight for both. Just make sure you stay away from mixing colors when lighting your green screen. Having a gradient from tungsten to daylight can wreak havoc when you try to key out your green screen.
Camera
It helps to put your camera in full manual mode and pay close attention to your shutter speed when shooting a green screen. Normally, you’d want to set your shutter speed double your frame rate but, when shooting a green screen switching to a faster shutter speed will help reduce motion blur when your subject moves or makes a gesture. When I film a greenscreen I typically target my shutter speed up to 1/100 sec. This isn’t a major increase of shutter speed but, it does noticeably help in getting a good key in the edit. I wouldn’t go overboard with your setting though as the stutter effect increasing your shutter speed gives can be irritating to watch.
With the advent of 4K cameras, shooting in 4K has proven to be a useful in the production. In my video production career, I’ve seen 4K cameras move from the Red Dragon Digital Cinema camera (which I used in the production of my short film, ‘At Your Convenience’) all the way down to the smartphone that I have in my pocket now. Shooting in 4K allows you to crop and Ken Burns your subject around the screen to allow room for graphics that you may include at your digression. Shooting in 4K also allows you to get a higher degree of precision when keying out your green screen and mastering to 1080P.
Another tip I’ve been recommended but, I haven’t managed myself is to shoot with an expanded color profile. Typically, I shoot in 4:2:0 but, if you have the equipment to shoot in something like 4:2:2 you can see better results when keying out your green screen due to the added accuracy in color.
Action
Unless you’re making an incredible major motion picture, I recommend keeping your subject seated in a single place. It’s fine to have your subject gesture and shift their position as long as you follow the shutter speed suggestion above. I say from experience that you want to keep your green screen shoots done with a single camera and in one take. If you try to use a B camera in your shoot it will be impossible to line up the background of the A and B cameras unless you a 3D model of your background that you can re-render when needed or you’ve taken multiple shots of your chosen background from multiple angles.
Blocking
Lastly, there is the blocking or how you arrange everything on your set. The green screen sets you can get online are typically make of a very thing muslin that can be seen through when stretched out. Obviously, this can’t be good for getting a good key while editing so, you’re going to have to implement either one of two workarounds. First thing you can work out is placing your green screen in front of a static plain wall. It doesn’t necessarily have to be black but, painting your wall black will definitely help. If you don’t want to get paint everywhere, the second thing you can do is drape another sheet behind the green screen. It can be anything–even a bedsheet–so long as it’s plain and not textured, you’ll be fine.
On another note, it helps to keep a distance between your subject and the green screen you’re filming on. There isn’t a specific ratio on the distance between your camera, your subject and the green screen but, it helps to hide any details or tiny imperfections in that may exist in your green screen.
Unfortunately, that is all I have for today but, if you have any comments or questions be sure to reach me at my “Contact” page and happy filming!
Ricker Video 