penny blacks, blues, and reds were printed with the plate position of the stamp indicated. For the first issues, there were letters in the bottom corners only, with the left box representing the row (A through T) and the right box representing the column (A through L). The pane was 20 rows down and 12 columns across (letters AA through TL).
Later issues had letters in all four corners. The top letters were the reverse of the bottom letters. Therefore, the 5th stamp of the 1st row would have letters A - E at the bottom, and E - A at the top. The top left stamp of the plate would have A - A at the bottom, and A - A at the top.
Now, can you guess what plate position your stamp came from?
No peeking at the answer.
NO PEEKING
OK, if you insist - H-row is the 8th row, and H-column is the 8th column. Every stamp in row 8, column 8 would have H - H in the bottom boxes. The later perforated stamps would have the same two letters at the tops.
Value is about a buck on a good day, assuming no hidden tears or creases. Check
ebay for sold examples of SG catalog number 43 or Scott catalog number 33 to see what they brought.
C.