Document / Blank Number
A unique combination of numbers and (or) letters which is given to every document. It may be applied by letterpress, laser engraving, perforation or printed by a printer. An ink which is used for printing numbers may luminesce in UV and (or) IR light and have magnetic properties. Special fonts and numbering devices are used for applying blank numbers.
a
b
c
d
e
f
g
Fig. 1. New Zealand. Travel document (Convention of 28 July 1951) issued in 2016:
a — page spread (pages 2-3). Polymer (data page) and paper substrate (page 3); b — the same. Data page. Document number. Relief laser engraving; c — the same. Zoomed fragment. Foaming and blackening (carbonization) of the substrate surface caused by the laser beam; d — the same. Page 3. Blank number. Letterpress; e — the same. Magnetic ink. Image captured by the magnetooptical scanner Regula 7701M; f — the same. Page 3. Blank number. Laser perforation; g — the same. Zoomed fragment. Perforated holes are flat. The edges of the holes and the adjacent areas of the substrate have traces of burning left by the laser beam