Hello, Horamkhet
If by "re-entry" you are referring to the colored semi-circles appearing at the bottom of the upper numeral ovals, this is caused by a slight shifting of the background of the design during printing. Since the background was printed separately from the frame, misregistration of the two was possible, resulting in "shifted background" varieties. The quality control at the printing office usually removed most of the radical shifts, hence their rarity today. One, however, finds more minor shifts such as the one on your stamp (notice that the background shift is also evident along the lower part of the central oval's outer frame which has become colored).
Below is a truly rare stamp (not in my collection, unfortunately
), where you can see a very pronounced shift of the background. It is Scott 50a, the imperf 7k of the 1889-1892 issue:
One sheet of this imperf variety is thought to have been sold in St. Petersburg (the absence of perforations might be explained by its intended rejection for further processing and release, due to the significant background shift). 4 copies are known to exist today, all cancelled in the same St Petersburg telegraph post-office. Realized $4.000 in the auction of December 2004. Ex-Mikulski.
Posted 08/05/2012 01:33 am
