Division 2 Each certificate shall measure 210 × 297 mm; a tolerance of up to minus 5 mm or plus 8 mm in the length and in the width may be allowed. The paper used shall be white writing paper, sized, not containing mechanical pulp and weighing not less than 25 g/m2. It shall have a printed green guilloche-pattern background making any falsification by mechanical or chemical means apparent to the eye.