These two scans were performed on two different prints of the same thing. The images don't line up perfectly. There seems to be some stretching going on.
Job: combine these two files into one high quality tif. Restore contrast. Eliminate water stain in lower left in the brown version. eliminate the folds in the 'b' version.
Create one excellent final tif.
==== Added on 08 Apr 2014, 21:36 =====
A better way to describe the alignment issue is that one image is warped compared to the other.