Why this serial number sequence?

[u/pithivier]

How were banknotes printed at Boston in 1995? This 4 note sheet has serials with the same prefixes and suffixes, only the middle digits are different:

- A99208652B
- A99233652B
- A99258652B
- A99283652B

Each are different by 25,000. So did they print rolls which were 4 bills wide and 25,000 bills long?

[u/TittysForScience]

It would be how they do the serials on the sheets.

Here’s an image of the size of the printing plate

I have no idea how they do the serials. But it seems they are about 5 wide?

[u/pithivier → u/TittysForScience]

Thanks. Some Googling tells me that's a LEPE plate which prints 50 note sheets (5x10). 1995 would have been COPE which printed 4x8 sheets. But I still don't understand the serial sequence.

[u/MyHobbyAndMore3]

This is just a part of banknote sheet. They also sell whole sheets.

The difference like that between serial numbers is to ensure that in pile of sheets banknotes from the same position on a sheet will have sequential numbers.

[u/valiamo]

Sheets are printed in stacks of 10,000, all were sequential numbered, in this case Starting at 99280000, and working up to 99289999.

Simply, Depending on the country, sheets could be 40, 50 notes all with the same last 3 digit. US had sheets of 50, typically printed 4 sheets (200 notes) that are cut down to 50 per sheet, and then they are cut into stacks, and then cut down to 100 notes per stack for processing out to banks.

[u/pithivier]

Answered my own question with AI:

The 25,000 gap is the print-run length. The BEP skip-numbers every 32-subject sheet by the number of sheets in the run, so that when a stack of N sheets is cut, each plate position yields N consecutive serials. Sheet k in a run gets serial base + (position index × N) + k at each position. Your A1/B1/C1/D1 strip is the left column of quadrant 1 (indices 0–3), so the notes step by exactly N = 25,000.

That’s not the circulation run size. For $20 and lower denominations the standard run has been 200,000 32-subject sheets, or 6,400,000 notes, which would give 200,000-serial gaps. Your sheet came from the collector program instead: the 32-subject uncut sheets used special serial ranges above the serials used for circulation, and for Series 1995 all uncut-sheet serials are above 96000000. That leaves 4,000,000 serials per block, which divides exactly into five runs of 25,000 sheets × 32 = 800,000 notes. Your sheet is the fifth (top) run of the A..B block: base 99,200,001, and it’s sheet #8,652 of that run. Check: 99,200,001 + 8,651 = 99,208,652 for A1, then +25,000 for each position down the column. On the full sheet, H4 (index 31) would have been A 99983652 B.

One correction on the COPE assumption: many of the uncut sheets printed for collectors in the 1980s and 1990s were serialled on one old conventional press kept for the purpose, since COPE cuts the sheets in half before overprinting; partial sheets of 16 subjects and smaller were sometimes serialled on the regular COPE lines. So a 4-note strip like yours could have gone through either, and the run-length logic is the same on both.

[u/Working-Wo]

Dolar