Panama Overprint Confusion

I have been working on Panama and Canal Zone varieties, and I have a very basic question. What is the difference between the 1903 Map of Panama red overprints (Scott 71-75) and the 1904-5 overprints (76-82)?

Scott's classic show illustrations of each set: The 1903 illustration shows the PANAMA printed in smaller type both reading up. The 1904-5 illustration shows a slightly larger overprint with one reading up and one reading down.

Te confusion is that there are all kinds of varieties that overlap. There are "15mm" varieties of the 1903 overprints and most stamps in both series have varieties of the two PANAMAs reading up and down.

What is the fundamental difference in these series? Am I missing something in these illustrations?

This question impacts the identification of Canal Zone stamps 19 and 20 too.

And is there an online or English-language guide to these issues that go a little deeper than the catalogs?

COPAPHIL (Colombia/Panama Philatelic Study Group) has information and in English. It has publications (see one below) discussing the stamps in more detail than Scott but using Scott numbers. Start there both for publications and perhaps information on who to contact. The website ( copaphil.org ) hasn't been updated lately but the APS reports the group, APS Affiliate #142 is active.


The Stamps of Panama 1878-2010: Vital Statistics by Federico Brid (2014). The 2008 first edition was titled "The Stamps of Panama 1878-2007: Vital Statistics" Over 140 new entries and changes have been made to the regular, air mail, back of the book and postal rate sections. The book is 150 pages and is comb bound. While COPAPHIL sells it, you could find a copy at one of the larger philatelic libraries in your region or the APS Library.

On line;
http://www.canalzonestudygroup.com/...on00evan.pdf

Thank you! The pdf is useful! I will track down a copy of the recommended literature.