As a postmark collector (PMCC #6333) as well as a stamp collector, I want to emphasize that this is NOT how postmarks are currently collected!
Collecting postmarks has evolved much like that of collecting stamped envelopes. In the early years, it WAS acceptable to collect postmarks in this manner. It was much like cutting around the die of early stamped envelopes.
By the mid-20th century, a
minimum cut size of 2 X 4 inches was considered acceptable. (The cut square era for stamped envelopes)
Postmark collecting has evolved into more of an interest in postal history as well as the actual postmark. While 2 X 4 cuts are still acceptable, the trend is toward collecting entire covers.
It's unfortunate that much postal history was lost by collecting only the CDS. Early collections of this type, however, are still collectable because for some small, early and short-lived post offices, it is the only way the postmark can be found.
If you want more information, check us out at
http://www.postmarks.orgDan
