2. Choose different reasons:
Choose green screen, because among the three primary colors of red, green and blue, green has the highest brightness, which is most beneficial to keying. It is more suitable for shooting daytime scenes, and it is mostly used for shooting distant views.
The blue screen is chosen because blue has the greatest contrast with human skin color. It is more suitable for shooting night scenes.
The choice of blue screen and green screen is mainly determined by the objects and clothes in the scene.
3. Different use areas:
Blue screens are widely used in Asia. Europe generally uses a green screen; Because most European eyes are blue. In order to facilitate the later stage, they used a green screen.
4. Different brightness:
In a scene, green is usually regarded as the clearest and brightest, so using green curtains usually does not require complicated lighting design, and it is not easy to produce black edges.
Blue needs twice as much light as green, so the blue screen is not as bright as the green screen.
Extended data:
The function of blue screen and green screen is to shoot objects on the same color (blue/green) background, so that the foreground and background can be distinguished by the hue information of the background color in post-processing, so as to achieve the purpose of automatically removing the background and keeping the foreground, which is also commonly known as "keying".
At present, the application of green screen is more than blue screen, because the green pixels in Bayer image array of most cameras are twice as large as red and blue, with the strongest signal, the least noise and the most brightness information. Blue noise is at most the darkest, so blue screen is generally not recommended.
However, whether using blue screen or green screen is to achieve some shots and scenes that are difficult to shoot in real shooting, which can not only ensure the safety of actors, but also reduce the shooting cost and make the whole shooting process controllable.
You need to pay attention to the color of the key background when shooting post-synthesis. Theoretically, digital synthesis can use any color background, but you should start with two points when choosing:
First, the color of the background should not be confused with the subject. If the two colors are too close, it will make the edge difficult to judge, which makes it difficult to key the image. It can only be erased manually, which of course increases labor and production costs.
Secondly, the color of the background should be close to the color of the light source, because the picture used for synthesis needs to be shot under the big screen, so the color of the background will inevitably be reflected on the subject.
The composition in outdoor green environment, if the green screen is used for keying, even if some light overflows to the main body, the audience will not be surprised.
References:
Baidu Encyclopedia-Green Screen; Baidu encyclopedia-blue screen