We believe, like many documents of the early 1900s, this marriage certificate was probably rolled up and placed in a tube for safekeeping. Some time later, when it was taken out, in a likely low humidity environment, the unrolling was enough to crack the paper in several places. At that time Scotch tape was used to repair it, and the problem there is that Scotch tape is laden with acidic compounds, particularly old Scotch tape. Around the perimeter you can notice a darker color. This was likely caused by a previous frame that it might have been in and the discoloration would have come from the acidic components in the frame. Further color distortion can be see in the rest of the document: the widespread lightened tones are due to sun shock.
Careful scalpel work and chemical softeners removed the Scotch tape residue. With several rounds of chemical baths we were able to treat the acid staining. Next we in-filled with paper of a similar condition, and gave it a new backing to help flatten it.Along the cracks, in-painting concealed the lost areas, and the faded writing was touched-up to return its original strength and weight.