It is important that the temperature and the RH in particular do not vary greatly from day to night or season to season. Fading is the most obvious symptom of this deterioration. Natural light and fluorescent light contain a high proportion of UV, so record materials should be exposed as little as possible. Unless light sources are filtered, they should be shut off or curtained when not needed, especially if documents are not stored in some type of enclosure.
Many plastics are harmful to documents of all types.
Plastic bags may be made from petroleum products and some envelopes are made from cellulose nitrate and cellulose acetate. The decomposition products of these plastics will hasten the deterioration of record materials. Most commercial photograph albums contain harmful plastics and adhesives, but specialty suppliers do carry enclosures made from acceptable materials. Food and Drink Food and drink should be prohibited in areas where documents are kept. They can cause direct damage by staining materials or making them sticky, and indirect damage by attracting insects and rodents.