Why can we not hang paintings in windowed rooms and allow natural sunlight to illuminate fine art?
Because sunlight is the worst possible source of fine art lighting. In spite of the fat that it is the light we all live in daily, and the light by which we see the beauty and the many forms and colors of nature, sunlight contains an invisible enemies that can damage human skin if you stay out in the sun for too long—ultraviolet light. Reason tells us that if UV radiation can sunburn our skin, sensitive oils and canvases will suffer an even more severe outcome if they hang for any length of time in a beam of sunlight. Infrared light is also part of the natural lighting spectrum, and although not as dangerous to humans as UV light, nevertheless has its own deleterious effects on canvas and oils. Infrared light waves are very hot and will dry out the oil and cause it to crack over time.
