Restoration is all about repairing damaged photos. Sometimes the damage is minor, in other cases it can be quite significant. Aged photos can be degraded and discolored from chemical residue, damage from rips and tears, ink bleed through from writing on the back and other types of damage.
These can all be fixed. Some will take more time than others but each photo is carefully analyzed for what needs to be done to bring back the original beauty. Visible damage is meticulously repaired by digital-processing, unwanted color casts, contrast and sharpening may also be altered to restore the original detail.