is a good way to control relative humidity and pollutants. Buffers and absorbers should be placed out of sight, in the base or behind the backboard of a case. If the case is to be painted, it is recommended oil paints be avoided; acrylic or latex paint is preferable. Display methods There are two kinds of objects displayed at the library and archival exhibition – bound materials and unbound materials. Bound materials include books and pamphlets, and unbound materials include manuscripts, cards, drawings, and other two-dimensional items. The observance of proper display conditions will help minimize any potential physical damage. All items displayed must be adequately supported and secured. Unbound materials 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. 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. Bound materials 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