Does anyone know what is going on with the DC $20 2017 series back plates? Back plate number seemed to have jumped by ~200 compared with face plate within span of a couple months. Compare blocks NF..D (FP 23, BP 67) April 2018; ND..A (FP 14, BP 109) May 2018; NG..A (FP 30, BP 221) June 2018 Either DC is trashing lots of BPs earlier than usual or wearing out quick.
This is a keen observation that you've made. It has been observed on the Where's George? forum that the back plate numbers of 2013 $20 notes have reached into the 700's, which is ridiculously high by modern standards considering these days the numbers reset with each new series. Heck, I recall the back plate numbers of the 1996 $100 notes didn't go above around 215 and those were printed for nearly four years. Anyway, while the cause seems to be a mystery, it may well have to do with the types of presses that are used to print $20 notes in the present day than the more traditional styles that were used in previous decades.
Funny that the FW facility is not experiencing this issue. And it is not happening on the other DC denoms. Assuming that same presses are used for all denoms.
They are not. As of a couple years ago (and I think it's still correct today), the BEP has eight of the new SOI presses and fourteen of the older I-10 presses. Washington has four of each; FW has the rest. I'm not absolutely sure what all's been printed on which press types at various times. Certainly all the 50-subject $1's are SOI products, because the older presses can't handle the larger sheets. Many $20's have been SOI but lately they seem to be mostly I-10. The $5's were all SOI for a while but I'm not sure about the latest batches. I don't think the SOI presses have produced any $2, $10, $50, or $100 notes, but there might have been some I'm forgetting. (If you get a quantity of new consecutive notes, you can identify the press type by looking at the rotation of plate numbers. The SOI presses use three different plates in rotation; the I-10 presses use four different plates in rotation.) As to the original topic of this thread: I have no clue what's going on with the $20 BP numbers. Historically, the FP numbers have generally run a bit ahead of the BP numbers, because the BPs print on blank flat paper but the FPs print on paper that's already covered in ridges from the back printing, which makes the FPs wear out just a bit faster. But the recent $20 series have had BPs running *far* ahead of FPs, for no apparent reason.... I doubt that there's a simple explanation involving the SOI presses, because the SOI $1's don't seem to exhibit the same pattern.
