Security Fibers
Fine coloured or colourless fibres located randomly in the paper substrate or on its surface. Fibres are incorporated into the paper during its manufacturing process and are distributed among other fibres of the paper pulp.
Classification
Perception degree with the naked eye:
- Visible security fibres which do not luminesce under UV, IR and other lights and may have magnetic properties;
- Visible security fibres which luminesce under UV, IR and other lights and may have magnetic properties (fig. 1);
- Invisible (transparent) security fibres which luminesce under UV, IR and other lights and may have magnetic properties (fig. 2).
Fig. 1. Visible under white reflected light.
20 000 Lebanese Pounds (2004)
Fig. 2. Invisible under white light.
Luminescence under UV light (365 nm).
50 Ukrainian Hryven (2004)
Colouring:
- Coloured security fibres;
- Colourless security fibres;
- Security fibres with alternate areas of different colours.
Fibre structure:
- Simple security fibres;
- Security fibres with variable cross-section of the profile (fig. 3).
a
b
Fig. 3. Security Fibers with variable cross-section. Zoomed image.
1 000 Russian Rubles (1997). Modification 2010:
a – under white reflected light; b – under UV light (365 nm)