"Jubilee" line.—Since 1887, the year of Queen Victoria's first Jubilee—whence the name—a line of "printer's rule" has been added round each pane, or plate, of most surface-printed British and British Colonial stamps, in order to protect the edges of the outer rows of clichés from undue wear and tear. The "rule" shows as a coloured line on the sheets of stamps.
Key-plate.—Stamps of the same design, when printed in two colours, require two plates for each value; that which prints the design (apart from the value, and sometimes the name of the country), and is common to and used for two or more stamps, is termed the head-plate or key-plate. And see Duty-plate.
A sheet of stamps of Gambia, composed of two Panes of sixty stamps each.
The single "Crown and CA" watermark as it appears looking from the back of the Gambia sheet illustrated above. The watermark is arranged in panes to coincide with the impressions from the plate.
EXAMPLES OF SOME PHILATELIC TERMS.
Knife.—This is a technical term for the cutter of the machine which cuts out the (unfolded) envelope blank, and is principally used in connection with the numerous varieties of shape in the United States envelopes, amongst which the same size may show several variations in the flap.