Photographs that are stored in damp attics, basements or shoeboxes as opposed to dry, acid-free environments run the risk of developing mold and mildew. Mold spots, if left untreated, can damage the photo beyond repair. Remove mold from photographs as soon as you notice dark spots on the surface.
Remove the photographs from their storage container and take them to a cool, dry area to allow the mold to dry out. An air conditioned room is ideal or an outdoor porch if the weather is cool.
Lay the pictures out on a flat surface. Stacking pictures can cause them to stick together. If there is already stickiness, slowly peel the photos apart to avoid ripping them or damaging the print.
Leave the moldy photos to dry before removing the mildew. Drying time varies according to the humidity in the air and the condition of the photos. Items that are covered in mold may need to dry overnight.
Assess the condition of the pictures by checking if the mold has turned from a solid to a powdery state.
Brush the powdery mold off of the photographs with a soft paintbrush or a microfiber cloth.
Consider putting the photos in albums or an acid-free container before returning them to storage to prevent a recurrence of mildew.