Printing with water-based ink may suffer from fibre rising and associated surface roughening due to the wetting involved. They swelled upon wetting and shrank upon drying, but remained flat. These changes were reversible. Other fibres were hollow and tube-like.
Some fibre ends rose out of the sheet surface upon drying.
Rewetting returned the fibre ends to a position largely within the sheet surface. Further drying resulted in rising again. Isolated groundwood and TMP fibres with tube shape showed the same types of contrasting behaviour, that is, collapse upon drying or retention of the tube shape. From these observations we conclude that fibre rising is limited to comparatively stiff fibres that maintain their shape upon wetting and drying. Rising occurred during drying, not during wetting and swelling.