Sheet Markings Cylinder Blocks with Control number.     The cylinder number on the left is 9 dot, the one on the right is 9 no dot. The control markings were used by the printers and were for accounting purposes. The control O over 44 indicates that it is the first half of the year 1944. The one bar under the 44, indicates the first reprint, the small block with 3 bars represents the 3rd reprint, or 4th printing using that same control number. Error of engraving - Obliterated Arrow These Marginal Arrows appear in the middle of each of the four margins of all photogravure Sheets. They can be shaped as a "V" or a "W" and can be either hand engraved, or photo-etched. On this 3d value, on Cylinder 27 the dividing arrow was incorrectly engraved between stamps 7 and 8 in the upper and lower margins. This was erased by lines and re-engraved in the correct position between stamps 6 and 7. The following illustration shows rows 1 and 20 of a sheet of stamps with the correction. Omitted and broken Jubilee Line On the 6d value, on Cylinder 37 the pickup bar (Jubilee line) under row 20/1 is badly damaged, and under row 20/10 is completely omitted.(SG. catalogue specialised Vol.2) This is a complete row 20 of a sheet of stamps showing these two errors, with the engraving arrow in the correct place. Where the pickup bar is missing under stamp 10, there is also a punch hole, for holding the sheets of paper in place. The apparent difference in colour is because the blocks were scanned with a black background. Introduction definitive stamps Definitive stamps watermarks High Value stamps Coil stamps and leaders stamps in booklets Sheet markings Airletters Commemorative issues Overprints