First, let’s discuss the need. All sunlight and some artificial light contain an invisible electromagnetic component called ultraviolet (UV) light. These light waves are much shorter than visible light and contain more energy (the same energy that causes you to sunburn). This higher energy creates a greater degree of heat and causes more rapid deterioration of the molecular structure of the pigments used in printing. Conservation glass should be used whenever you are framing sentimental, valuable, limited edition and one-of-a-kind artwork. Conservation glass is clear glass (preferably float glass) to which an ultraviolet (UV) inhibiting film has been applied. Conservation glass blocks about 97 percent of the UV rays, compared to 46 to 50 percent blocked by regular clear and non-glare glass.