Refers to a fibrous composition of the substrateThe physical media or support on which the image is printed, such as paper, polymer or hybrid, etc. More used for banknotes, where there are fibresA banknote security feature incorporated randomly during the manufacture of the paper. The fibres can be made of silk, plastic or metal, and may be visible, invisible, or fluorescent under UV light. More of cotton and other materials such as linen or polyester. The purpose of using mixed fibres is to improve the mechanical properties of the paperSee Banknote paper. More, such as scratch or crinkle resistance.