Projection screens are installations for projecting an image for the view of an audience. They can may be permanently installed (like movie theatres), semi permanent or mobile (tripod). White/grey colored screens are used to avoid any discoloration to the projected picture, while optimum brightness of the screen is affected by several parameters, including the light level of room and the luminous power of the projection device. Flat screens may be prefered, depending on the optics used to project. Curve screens are also available in market, even though less popular compared to flat screens, but Bogazici do no offer them. Front and back projection are both possible. In the latter way, the image is sent through the transparent projection.