This photo was taken sometime during the 1920s. After decades of sitting around in various environments, it cracked down the middle and faded unevenly, both in contrast and its original toning. To make things worse, the crack was taped over and after time the tape began to do some damage of its own.
To resolve this, I started with a high-resolution scan of the image. Then, I focused on fixing the crack and other various damage. Once I had dealt with all the damage, I evened out some of the tone and color shifts.