I purchased this vertical imperforate pair which was listed as 1597e from a dealer. I assume it is correct and have no reason to doubt it. What I would like to understand is how to tell the difference between a 1597c and 1597e. Scott describes them as below:
1597c - Vert. pair, imperf. btwn and natural straight edge at bottom
1597e - Imperf., vert. pair
I would like to add clarifying info to the Tagging and Luminescent DB on what the difference is. I assume they are referring to a stamp from the bottom row for 1597c. How does one tell if it is a natural straight edge versus one that someone cut very carefully?