Paper sheets reveal pronounced changes in shape and dimensions upon exposure to variations in moisture, which comprises digital printing operations. These are observed in the form of curls, waviness and buckling at the sheet-scale of paper. In digital printing, this undesired behavior is due to the fact that the moisture is rapidly absorbed in paper and thereafter evaporated within a short period of time.

These dimensional changes originate from the single fibre level, which affects the fibre network through the inter-fibre bonds (regions where the fibres overlap). At these bonds, an interaction of the hygroscopic and mechanical response of the fibres occurs, entailing micro-stresses and associated sheet-scale deformations. In order to understand this macro-scale behavior of paper, it is essential to study the complex fibrous network at the micro-scale.

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