Distributed Recommendations on Peer-to-peer File Sharing Systems

A masking device for use in photographic printing, disposed between a photographic printing light source and a lengthwise sheet of photosensitive medium and adapted to define the printing area, the masking device having a pair of moving bases capable of moving in the widthwise direction of the photosensitive medium, a pair of widthwise-end mask members supported on the moving bases and moved in response to the movement of the moving bases so as to define the printing area in the widthwise direction of the photosensitive medium at the time of printing of a non-framed image, and a pair of auxiliary mask members mounted on the widthwise-end mask members and adapted to define the printing area in the widthwise direction of the photosensitive medium at the time of printing of a framed image. The printing area is defined by the widthwise-end mask members when a non-framed image is formed or its is defined by the auxiliary mask members when a framed image is formed.