1908-1909 Perf & Imperf #331-347

1908-1909 Perforate & Imperforate #331-347
The Washington-Franklin Definitive issues from 1908-1922 utilize only two basic stamp designs. Yet they account for almost 200 different major varieties, due to differences in perforation, watermark and printing processes (flat, rotary, and offset) as the Postal Service experimented to find the best way to produce a postage stamp.