I would imagine that if one had the right kind of equipment and the monetary motivation to do so, a specialty company copier could gradually increase the size of the 5 x 8, and, after increasing the size each time before printing, use whatever functions necessary to return clarity and definition to each larger image. Probably your favorite copier in town, if not able to do so, could recommend a company that could. They make the process look pretty easy in the movies about the FBI. Wish you luck!