1997 version

• fibres 6 mm long, invisible in daylight, with bluish fluorescence; visible fibres with yellow fluorescence; part of the portrait (including the name), the blind code and the name of the engraver with blue-green fluorescence

1995 version

• versions - only fibres 6 mm long, invisible in daylight, with bluish fluorescence

1993 version

• only fibres 6 mm long, invisible in daylight, with bluish fluorescence