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 the engraving arrow in the correct place. and the missing jubilee line. Where that line is missing under stamp 10, there is also a punch hole, for holding the sheets of paper in place during the stamp production. The apparent difference in colour between the blocks and the strip 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 Forces Mail and Airletters Commemorative issues Overprints Wartime slogans