Canada #704i, 732/750 1977 Commemoratives - A Group of 15 Canada Post Official FDC's Franked With Singles, Pairs and Blocks, Different Envelope Fluorescence Levels
A group of 15 official Canada Post FDC's franked with singles, pairs and blocks of the 1977 Commemoratives issues, all printed on the standard papers for the issues involved. Several apparent duplicates are actually different with regard to the envelope fluorescence, as detailed below.
The envelope fluorescences vary widely:
732 is DF-fl.
733-734 is DF-fl.
704 is on both DF-fl and LF-fl.
738-739 is MF.
736 is DF-fl.
735 is LF-fl.
743, 743 and the combination FDC are MF.
742 is DF and HF.
744-47 is DF.
748 and 751 are NF-fl.
Envelope fluorescence is an aspect of post-1971 FDC's that is completely ignored by all the catalogues. I'm not sure why, as FDC's after 1971 are a standardized Canada Post Product, with issue specifications - exactly the same as the stamps on them. The envelopes are but one component of this product in the same way that tagging is to a stamp, or gum is to a stamp, and in many cases you will see varied reactions under UV for FDC's that otherwise look exactly the same. To the extent I see differences I will describe them here.
