To make paper appear brighter white, manufacturer's add chemicals to the base stock or coating. The chemicals, called Optical Brightening Agents (OBAs), convert ultraviolet light and re-emit it in the visible blue spectrum. They "fluoresce" at a point that is just barely within our ability to see. This additional light causes paper to appear brighter white. Without OBAs, most paper would have a warm, almost creme color.
Good or Evil?
Much argument and conjecture regarding OBAs exists on internet forums and in professional circles. The main argument is that these chemicals will “burn out” over time, leaving the paper with a warm or dull appearance. In turn, whites and light colors in an image will shift. You have seen this evidenced in most old photographic prints. The question is do OBAs mean your prints will fade or otherwise fail earlier than a traditional photo print?
Bear in mind that OBAs require exposure to UV light to exhaust their potential. Prints stored in the dark, or those under UV inhibiting glass will not experience the same shift over time.Â Now consider that OBAs exist for a reason. The demand for bright white paper moves manufacturer's to put OBAs in most inkjet media. As a whole, consumers call for bright white media, and that is what dominates the supply. Finally, OBA technology is quite refined. The chemicals used today are more stable than ever before. If you treat your photo prints with respect, storing and displaying them properly, you minimize potential problems.
For those still unmoved by the arguments defending OBA use, warm tone media is the answer. Low and no OBA content fine art, Baryta, and even RC paper to are readily available. Check with the manufacturer to determine which papers are in this category.