For getting the optimum results selecting right combination of projection screens is very very necessary. You will come across different types of screens that are available on the market today. Some of these screens are operated manually. On the other hand, some types of screens are operated electronically. Then, the screen surface that best fits for projection and viewing requirements. . For example for using slide projector and video projector choose screen surface for video projector. If you are not aware about the ways to use it then you should go through the user manual, which is available with the product.