If you are about to shoot some green screen projects, consider some of these tips for a smooth post-production process.
Estimate the size of the green screen by considering the complexity of the scene you are going to shoot. The room’s depth and the focal length also need to be considered.
If the shooting is going to be done in a dedicated studio, you need to pick a location with enough space. The shooting area quickly fills up when you add lighting and props to the area. The movement of the cast and crew becomes very difficult in such tight spaces.
The green screen needs to be set up on a very stable surface. The stands need to be solid, and it’s best to use numerous sandbags to make them stable. It will prevent the screen from falling on top of the cast. Use sandbags on the lighting equipment as well.
Make sure that anyone who will be in front of the camera is not wearing anything green. The only exception is if the green elements in the costume will always be a significant distance from the edge of the actor’s body. Remember to check the edges of the body from several angles.
However, it will still increase the post-production load since you will need to use garbage masks while editing. It will not be like shooting with the software available at sites like https://bigvu.tv/. Their technology automatically replaces green screens with any image or video. It also lets you customize backgrounds to appear in a loop.
Be wary of dark and shiny footwear. You also need to be careful with reflective glasses or sunglasses. If the actor or presenter needs to have glasses on, they shouldn’t move their heads too much. If you don’t have a good camera or a well-lit green screen, it is also advisable to avoid any yellow-coloured clothing on your actors.
Have the background footage prepared before the shoot so you can match the on-set lighting as closely as possible. If that is not possible, choose the lighting setup to reflect the time of day in the scene. You need to have two sets of lights. One will be focused on the screen, and the other will be focused on the performer.
The green screen should be lit first, followed by the performer. There should be enough distance between the performer and the green screen, so there is no shadow on the screen. Also, the green screen should be lit evenly. LED tubes and tall LED panels are the best bets here. Other things to use are softbox modifiers and backlights. These measures will help separate the subject from the background and eventually make keying much easier.
Separate the foreground and the background using luminance and not just color separation.
For instance, if the performer has dark green clothing, increasing the light on the green screen will create more contrast. This luma difference will help in the post-production. On the contrary, avoid mixing different color temperatures, as that will make keying much harder.
You need to stretch your green screen to prevent folds and wrinkles. A smooth transition between the floor and wall can be created by using card green screens for the floor. On the performer, check for green tattoos and try to hide them. The camera should be kept on a tripod with no zoom or panning. If you want to add movement to the scene, put markers on the green screen and track those in post-production. And remember to use green tape to create those markers, or it will be very difficult to remove during post-production.
Do not use a fog or smoke machine. It will make keying much more complicated if the camera you are shooting with has h.264 compression enabled. If you are using a fan, be careful of how the wind is hitting the green screen. If the green screen is cloth, you will need to deal with moving shadows later.
Remember to check the footage on a large monitor on the shooting floor after each take. The main thing that you want to check is whether the talent is within the green screen background throughout the shot. If you want to be doubly sure, import the background footage using After Effects and check the scenes.
These are some tips that you can use to ensure that you don’t waste any unnecessary time and resources on post-production.