Graphics, especially watercolors, are very sensitive to light. The effect of light is cumulative and should not exceed 50 lux. Rooms should be darkened when not in use. Ultraviolet light is especially detrimental; however, even light with no UV component is very harmful. Temperature should be as low as possible and the humidity should not exceed 50%. Air pollution should be eliminated if possible with a purifying air conditioning plant. -- AATA