When the weather station makes weather forecast, the host stands in front of a blue hanging cloth to host. How does the weather forecast make it look like it's on TV?

The reason for doing this is simple and convenient for computer processing. When the color part of the curtain is transparent and needs a background, the main special effects come out. It makes sense to use blue as the color of the curtain, because the subject is usually a character, and the rarest color in people's clothes, hair and skin color is blue, so the application of blue curtain should be the most extensive, and people gradually call the stunt background blue curtain.

In fact, the blue screen has gradually become a historical term, not only the color is not limited to blue, but also the requirements for the background color are getting lower and lower. Even if there is no curtain body, it is not difficult to dig it out for stunts (the background is the same). You can see that there are ancient news footage in Forrest Gump, and it is seamless to dig out the original historical figures and add Tom Hanks's modern performance image.