<P> Unbound materials, usually single - sheet items, need to be attached securely to the mounts, unless matted or encapsulated . Metal fasteners, pins, screws, and thumbtacks should not come in direct contact with any exhibit items . Instead, photo corners, polyethylene, or polyester film straps may hold the object to the support . Objects may also be encapsulated in polyester film, though old and untreated acidic papers should be professionally deacidified before encapsulation . Avoid potential slippage during encapsulation--when possible, use ultrasonic or heat seals . For objects that need to be hung (and that may require more protection than lightweight polyester film), matting would be an effective alternative . </P> <P> Objects in frames should be separated from harmful materials through matting, glazing, and backing layers . Matting, which consists of two pH - neutral or alkaline boards with a window cut in the top board to enable the object to be seen, can be used to support and enhance the display of single sheet or folded items . Backing layers of archival cardboard should be thick enough to protect objects . Moreover, any protective glazing used should never come in direct contact with objects . Frames should be well - sealed and hung securely, allowing a space for air circulation between the frame and the wall . </P> <Dl> <Dt> Bound materials </Dt> </Dl> <P> The most common way to display bound materials is closed and lying horizontally . If a volume is shown open, the object should be open only as much as its binding allows . Common practice is to open volumes at an angle no greater than 135 ° . There are some types of equipment that help support volumes as they displayed openly: blocks or wedges, which hold a book cover to reduce stain at the book hinge; cradles, which support bound volumes as they lay open without stress to the binding structure; and polyester film strips, which help to secure open leaves . Textblock supports are best used in conjunction with book cradles where the textblock is greater than 1 / 2 inch, or where the textblock noticeably sags . Regardless of its method of support, however, it is worth noting that any book that is kept open for long periods can cause damage . One should turn an exhibited book's pages every few days in order to protect pages from overexposure to light and spread any strain on the binding structure . </P>

Who decides what work will go in a show and how to display it