How to Set Up Your Light and Background in the Virtual Studio?
Nov 15 2017
Have you ever wondered why Hollywood blockbusters are so captivating? People willingly invest significant money and time to immerse themselves in the love, hatred, and drama unfolding on the big screen. There's an irresistible magic that draws audiences in, and that's what we will explore today.
A compelling film has a gripping storyline and involves sensory stimulation through sound, light, and visually stunning special effects. The visual feasts presented in movies, unfolding alongside the plot, provide audiences with an immersive viewing experience. However, how can low-budget productions achieve similar effects? Even without the budget for elaborate sets, computer-generated animation, and virtual backgrounds can assist in creating a unique world as envisioned by directors and screenwriters!
The background is the first element to be constructed. Its height should exceed that of the main characters since actors will stand in front of a green screen during shooting. A green screen with a height of 2.4 meters generally meets the requirements for most film shoots. Keeping the green screen clean and wrinkle-free is crucial to avoid unnecessary shadows and reflections. Uniform lighting is essential for the green screen; if possible, it should not touch the floor. The green screen stand can be set up in an arch shape for full-body shots, gradually descending to the floor.
Illuminate the background first for virtual scenes and then address the key lighting for the characters. Lighting the green screen is similar to lighting a regular scene, with the main light illuminating the actors and fill lights brightening the background. Backlights help separate the actors' hair from the background. When lighting for green screen removal, ensure sufficient lighting for the green screen. Then, arrange the lighting setup for your main characters.
The first two lights are typically used to brighten the background. Place lights 1.5 meters in front of the green screen and another light parallel to the background 5 feet away. Set the lights to their brightest and raise them to 1.8 meters. Adjust the angle of each light until the background lighting is even. Even background lighting is crucial for effective green screen removal, as shadows and overexposed areas can only be partially removed, leaving green artifacts in the background.
Position the characters at least 1.5 meters from the screen to prevent shadows from the main light on the background. The main light should be set at a height of around 2 meters. Place your characters between the background and the fill light, ensuring they are parallel to the green screen, allowing the fill light to eliminate shadows on their sides and shoulders. The backlight helps with the green screen removal effect. Use standard daylight color temperature (5600K) for the main lights. Background lights can be tungsten or orange-colored to reduce green screen reflections on the characters, separating them from the background. Setting background lights to 3200K is particularly helpful for lighting blonde or light-skinned actors.
The background should not be brighter than the main subject. With all lights at full intensity, your main characters 1.5 meters from the screen, and the main light set 1 meter away from the actors, you should achieve the desired effect. Adjust the fill light intensity to 75%, depending on the actors' skin tone and the green screen material. Finally, use the camera to assist in adjusting the final lighting, as the exposure on the camera screen may differ from what the naked eye perceives.
Avoid overexposing the green screen, as bright screens can lead to excessive green light on the actors, especially on hair and shoulders. White balance settings are crucial for green screen shooting, as subtle changes in camera settings and any fluorescent lights in the room can affect white balance. Place a white sheet in front of the actors to set the camera's white balance before shooting.
You might wonder about the differences between blue screens and green screens. The key question is how to choose the right keying color. Blue screens were more common in the past because blue is the complementary color to skin, minimizing its impact on skin tones. However, many white people have blue eyes, so they could be mistaken for the background and get keyed out. Green, being brighter, requires less light and is less prone to creating black edges. Moreover, cameras are more sensitive to green. Hence, green screens are more prevalent in Western productions now. If the scene contains green, choose blue, and vice versa. The background color can be adjusted based on the subject's color, ensuring no color clash with the background. Green reflects twice as much light as blue, leading to potential color spill issues. Avoid shooting foreground elements with the same color as the background to prevent unintended keying. Most modern cameras use the green channel for luminance transmission, making green screens more efficient with fewer lighting requirements and minimizing spillage on actors' edges.
In conclusion, background removal is a fundamental technique in filmmaking, whether a high-budget production or a low-budget film. It's often a cost-effective choice, as constructing real sets requires time and money. Using CG animation can expedite the workflow and allow for real-time adjustments during shooting. This flexibility is invaluable, as discovering issues with the effect in post-production can be too late.
