negative (Scope note)

Negatives can be made of glass or from a variety of polymers. Modern ones tend to be polyester based or cellulose acetate butyrate but the older ones, if not made of glass, are often cellulose acetate or cellulose nitrate which are not very stable and have many associated degradation problems (acidic off-gassing, fire hazard, warping, crazing, brittleness, stickiness, etc.). The Material entered should be 'glass' or 'plastic' unless it is identified, in which case a more specific term should be entered.