I hope the following gives you some kind of idea about the basics on these # on # Plate Number Coils

Here's the not so-short version of the story - These # on # are a very popular arena in the Plate Number Coil Stamp collecting Nation. These # on # Plate Number Stips of 5 are short for "Back counting number behind the front plate number" - now that doesn't sound or look to complicated (see photo: ) but this doesn't occur very often and most rolls are used by the thousands every day by bulk mailers. The plate and back counting number don't align more than 1 out of 5 rolls and many rolls have verying different combinations since the plate numbers are spaced eithr 10, 14, 20, 21, 24, 28 or more stamps apart and the back numbers are either every 10 or 20 so you do the math. Gummed stamps differ from self-adhesive stamps. Some rolls have one of these # on # plate strips occur every 420 stamps and some occur every 70 stamps (in the rolls that the back number doesn't fall one stamp to the left or right of the front plate #). Then you throw in the fact that rolls of 500 have 3 digit back number, rolls of 3000 have 4 digit back number and big rolls of 10,000 have 5 digit back numbers....oh, I'm not done...the back numbers come in different ink colors: black, pin, aqua, purple, and a very dark purple. Ocassional errors occur and some stamps also come with middle back numbers instead of just numbers printed near the top or bottom of each roll of stamps.  If you are looking for a complete list of all these number on number combinations you should buy the PNC3-org's annual catalog of all plate number coil strips. It prices and identifies which ones have black back number and which ones are really purple. (see photo showing slight difference .

The new 60 state flag issue of coil stamps does not have back numbers, but the 2008 version of the 1cent tiffany lamp does have back numbers since the roll sizes are 3000 stamps or larger.

   Note: This area of collecting is probably going to be very under-rated by 2008 dollars with much upgrowth opportunity becise they can't go back and produce more back number rolls. Those 25 cent bulk rate rolls of 3000 and 10000 were mostly used by huge bulk mailers and thus maybe 90-95% of the inventory of possible back numbers landed in a garbage can. Then you have to figure that of those saved by dealers or collectors the non-plate number stamps have to be used or sold off at a serious discount - because they are bulk rate stamps and not good for first class without a permit number. I'll bet 15 years from now that most of these # on # PNC's will be worth 5-10 times what they go for now. Good Luck - have fun - thanks for the read,Dave