the difference is the color

Like if you want to edit the background when there is green objets in front, you should use a blue screen, but if there is blue objets, use a green screen

Good luck!

You can also choose whatever color you want, such as white screen, yellow screen, red screen, and etc. The only thing that matters is, object shouldn’t have any color that resembles the screen.

The actual phrase used for green and blue sceening is Chroma key compositing, or chroma keying, which is a special effects / post-production technique for compositing (layering) two images or video streams together based on color hues (chroma range). The technique has been used heavily in many fields to remove a background from the subject of a photo or video – particularly the newscasting, motion picture and videogame industries. A color range in the top layer is made transparent, revealing another image behind. The chroma keying technique is commonly used in video production and post-production. This technique is also referred to as color keying, colour-separation overlay (CSO; primarily by the BBC[2]), or by various terms for specific color-related variants such as green screen, and blue screen – chroma keying can be done with backgrounds of any color that are uniform and distinct, but green and blue backgrounds are more commonly used because they differ most distinctly in hue from most human skin colors. No part of the subject being filmed or photographed may duplicate a color used in the background.[3]

It is commonly used for weather forecast broadcasts, wherein the news presenter appears to be standing in front of a large map during live television newscasts, though in actuality it is a large blue or green background. When using a blue screen, different weather maps are added on the parts of the image where the color is blue. If the news presenter wears blue clothes, his clothes will also be replaced with the background video. A complementary system is used for green screens. Chroma keying is also used in the entertainment industry for special effects in movies and videogames. The advanced state of the technology and much commercially available computer software, such as Pinnacle Studio, Adobe Premiere, and dozens of other computer programs, makes it possible and relatively easy for the average home computer user to create videos using the “chromakey” function with easily affordable greenscreen or bluescreen kits.

Remember that if you use Green or Blue screen for your video, you need to have a number of good, bright lamps for the object and the screen background. Three things stand out for make a good quality effect using green screen:

1. Good lighting on the minifig and separate lighting for the green screen. If you have too much lighting on the green screen it will reflect onto the minifig or set and give you a green blur on the image.
2. High quality camera with a nice clean focus point. You don’t want a blurry edge of the minifig or it will make it harder to remove the green from the image.
3. The correct distant your minifig or set should be from the green screen backdrop. Too close and it will add green to your object, too far and it maybe too dark. You have to play with these three issues to get a good quality image that can be affected with chroma key editing.

sorry to gloat, but I have a 3m x 6m green screen…