Philatelists on the other side of the Channel began the precise study of the new Machin stamps, the one with the new secutiry measures to avoid their reuse.
The trained eyes of Ian Billings has already discovered variations/errors/types (?)es of these young stamps.
Inside the Design Classics commemorative booklet, he remarked the cutting in two of the security slits. Printed by Walsall. In sheets and by De La Rue, the slits are in two semi-ovals (or two "cuts" in Billings' text).
Now, he can add that the gap is wider on the definitive booklet stamps, issued 31 March 2009.
Moreover, he makes us aware of a second difference that isolate stamps from the commemorative booklet: these Machins got simulated rounded teeth when United Kingdom's adhesive stamps got horizontal teeth.
I let to Machin Mania the presentation of printing cylinders and marginal mentions on stamp sheets. But, I understood there these "dots"/"no dots" thing I heard during my London season.
Finally, the great specialist, Douglas Myall, aka Deegam, proposed two new terms adapted to these new stamps in his Deegam Report #80. He placed them in the public domain to help others describe the stamps. Here they are thank to Machin Mania:
OFNP/PSA: non phosphor neither fluorescent paper / P for the PVAl water soluble layer ; S for self adhesive and A for acrylic adhesive. And because the PVAl was removed to ensure that uncancelled used stamps will not be used again:
The Complete Deegam Machin Handbook lists all known types and variations of the Machin stamps. It is available on cd-rom for thirty nine pounds sterling, updated with the Deegam Reports.