Mold in paper cannot begin or survive unless the humidity is 70% or above for a period of time. Consequently, air conditioners or dehumidifiers are a solution for excessive humidity which allows mold growth. All light harms paper to some degree. Non-glare glass is not ideal because of its translucent rather than transparent qualities. Because paper expands with moisture and contracts with dryness, cockling may occur, but should be tolerated to a certain degree.