Most of us, myself included, put our photographs in a frame with glass and hang them in a desired location without much thought for what happens to them once they’re on the wall beyond our pleasure in seeing them there.
To keep your beautiful, precious photos safe while on display, here’s some very useful advice from a friend of mine who works on photo restoration:
Hang your photo in a place where sunlight will not directly fall on it. Sunlight can damage the photo, and wash-out or even change the colors on the photo. Also there is the possibility of water damage due to condensation inside the frame if the environment experiences wide temperature swings, or if the photo is in direct sunlight.
Never let the glass touch the photo directly, always use a mat between the photo and the glass even if it’s just a small one. When the photo touches the glass for a long period of time, there’s the danger of damage. The emulsion, the thin coating of chemicals on a photo print, could stick to the glass.