While losing a half-inch off the waistline seems impossible for many of us, pages in the Mercury News and Contra Costa Times will soon be going from a width of 12 inches to 11 1/2 inches to save money by reducing the use of paper. The printing trade publication Newspapers & Technology says that 25 MediaNews Group papers, including those in the Bay Area, will be shrinking their web widths to 46 inches. A 46-inch Web translates into a page 11 1/2 inches wide. The Chron still is using a 50-inch web (resulting in a 12 1/2-inch wide page). MediaNews is also installing PDF-to-plate technology, something Southwest Offset in Redwood City has been using for several years.