The three "Millennium Definitives"!

From the outset, collectors suspected that the stamps from the different printers would be identifiable, despite the seemingly uniform design.

Douglas Myall of the Deegam Catalogue describes the stamps thus: 

"Because the millennium Machin head has no background there is no 'frame'.
To fill the space and maintain aspect ratio, part of the image had to be omitted; the part chosen was the base of the portrait, i.e., the corsage.

However, the amount omitted differed with each printer. This is best seen by looking at the space between the base of one image and the tip of the diadem on the images below.

This gap is 0.1mm on a Questa stamp, 0.2mm on a De La Rue stamp and 0.5mm on a Walsall stamp from panes of 10. (It is 0.6mm on a Walsall stamp from the pane in the Special by Design prestige book to be issued next month.)

While these differences are minimal, they are constant and are just one of the features by which singles of the different printings can be distinguished.

Thus, collectors can defeat Royal Mail's intention of having three printers create identical images by supplying them with the same digital head on a CD ROM. "

These enlarged images of parts of the stamps might help collectors to distinguish single stamps in their collections.