Perforation
Holes in the substrate, which are arranged in a certain order. They can form a pattern (a holder’s portrait, a document number, etc.).
Perforation can be laser or mechanical.
Laser perforations are created with a laser beam. In this case the holes are of proper shape, have smooth edges and no ridges. The diameter of laser-perforated holes is smoothly reduced from the first perforated page of the document to the last one. Traces of burning left by the laser beam are visible around the edges of the holes. The holes may differ in form: round, triangular, square, asterisk-shaped, etc.
Mechanical perforation is performed with the help of needles or pins. Consequently, ridges are felt to touch on the back of the substrate.
a
b
Fig. 1. Australia. Travel document (Convention of 28 July 1951) issued in 2009:
a — additional page 3. Paper substrate; b — the same. Document number. Laser perforation. Traces of burning (marked with arrows) left by the laser beam are visible around the edges of the holes
a
b
c
Fig. 2. Republic of Belarus. Passport issued in 1997:
a — page 16. Paper substrate; b — the same. Document number. Mechanical perforation. Front side. Indentation of the substrate at the edges of the holes; c — the same. Back side (page 15). Ridges at the edges of the holes (marked with an arrow) left by the perforating tool
a
b
c
Fig. 3. Sweden. Passport issued in 2012:
a — data page. Polymer substrate; b — the same. Secondary image of the holder. Laser perforation. Transmitted light; c — the same. Laser-perforated holes. Flat, smooth edges. Transmitted light