Light--Never hang or exhibit photographs in direct sunlight. Try to avoid strong indirect daylight. It's a good idea to change prints frequently if they hang in strong light situations. Ultraviolet light is what you want to avoid most. Many fluorescent tube lamps give off strong ultraviolet light, and filters are available and should be used. Also, you can purchase ultraviolet-shielding Plexiglas or glass when getting your photographs framed. Most recent color prints have a UV coating that protects the photograph, but this is a recent innovation. Older color photographs will need additional protection for color shifts, etc.
Heat and Humidity--Try to avoid extremes of heat and humidity. Keep photographs away from fireplaces, radiators or other heating devices. When storing photographs, keep them out of damp basements and hot attics. It is best to keep them at a constant temperature humidity; museums try to keep the temperature at around 65 degrees Fahrenheit and the relative humidity at about 40% (although color photographs are often kept at much cooler temperatures). You may find that you will need to keep your air conditioning on in order to best preserve your photography collection. If the humidity is too high, be on the lookout for foxing, a type of mold growth. Corrosion can become a problem for daguerreotypes that are stored in locations near the ocean.External Pollutants--Where you hang and store your photographs can make a big difference. If you choose the wrong place, they may become damaged. Here's a list of what you should try to avoid: smog, fumes from fresh paint, cleaning solvents and adhesives, motor exhausts, burning wood and smoke of any kind, rubber bands and other rubber based products (which contain sulfur), and moist ocean air. Also, try to avoid displaying photographs where food is being prepared (such as in a kitchen or a restaurant). The best way to protect your photographs is to remove them and place them in a safe area whenever the conditions become extreme. Heavy duty air filtration systems are commonplace in museums, but most private collectors do not have them.
Insects--Keep an eye out for insects. Insects, such as silverfish, have been known to eat the emulsion on prints and are attracted to certain types of glue such as wheat-flour paste. Also insect secretion can stain a print. A properly framed photograph is your best protection. If you see an insect in a framed photograph, remove it immediately and check for others. If you store your photographs, occasional check the storage area for nests of various kinds.
Earthquakes--Damage can be avoided by securely attaching frames to the wall. There are several types of security hangers available, consult with you framer. Make sure to use good quality picture hanging hooks, make sure to use more than one for better balance, and make sure that they are securely attached to the walls (preferably in a wooden wall stud). Use only UV Plexi instead of glass for your glazing.
Framing--Make sure you take your photographs to a framer that is experienced in handling photographs and fully understands archival matting and framing.
Restoration--If your photograph is damaged and in need of repair, consider your options carefully. Sometimes it is best to leave as is, because all restoration steps carry some risks. Proper framing, display and storage may be your best option instead of restoration, but a professional photography conservationist can help guide you in this decision. Contact your local museum for suggestions for good local photography conservationists. But make sure that they are experienced specifically with photography and are not just paper conservationists.
Moving Artworks--If you are involved with a major move, make sure that your artwork is protected from the elements, as well as from uneducated movers. Look out for weather problems: wrap your artwork in plastic to prevent water damage. To protect frames make sure your movers use bubble wrap and handle them as fragile objects. Corner protectors (cardboard slip on corners) are also available.The above information reprinted courtesy of: