Abstract: A masking apparatus for masking portions of the viewing surface of a projection screen. The masking apparatus includes an upper roller, upon which is wound an upper masking screen, and a lower roller, upon which is wound a lower masking screen operatively connected to the upper roller. When the upper roller is rotated in a first direction, the upper masking screen is unwound and lowered to mask the upper region of the screen and the lower masking screen is unwound and raised to mask the lower region of the screen. When the upper roller is rotated in an opposite second direction, the upper and lower masking screens are wound to non-masking alignments. In an alternate embodiment, the masking apparatus can be used to mask side regions of a projection screen viewing surface.

Abstract: A retention system for operable flexible shades. The system includes a flexible sheet of a size which substantially covers a wall opening, and which is connected at its top edge to an operable roller. A side casing having a channel is mounted at each side edge of the wall opening. A plurality of generally parallel stays is applied to one of the opposing surfaces of the sheet for providing rigidity to the sheet, and to assist in keeping the edges of the sheet within the channels when a positive pressure is applied to the sheet. A grommet sized to remain within a channel during the rolling and unrolling of the sheet is affixed at each end of at least some of the stays.