It can absorb moisture from and release moisture to its surroundings.
This happens predominately at the sheet edges.
This inconsistent moisture loss will cause a sheet to distort.
Exposed to a dry atmosphere will cause edges to shrink resulting in a saucer shaped sheet and the effect known as tight edges. Exposed to a damp atmosphere the sheets will expand whilst the middle remains in its original shape causing baggy edges.
The key to successful running in laser and inkjet printers is to ensure that all paper remains protected from the atmosphere to reduce the gain or loss of moisture.
Always leave paper in its original waterproof wrapping until use.
Whenever possible allow the unopened paper to acclimatise to its surrounding temperature before opening and using.
The time taken for paper to acclimatise to its surroundings varies according to the weight of paper involved and the temperature gradient. It can take as long as two days.
Paper should always be knocked up into square stacks and covered before use.
When not using, re-wrap or cover paper to assist moisture protection.
Do not store paper near sources of heat or near open doors and windows even when wrapped.
Paper should wherever possible be protected from drastic variations in temperature.
Paper should always be stored flat and clear of the floor and therefore clear of damage or damp.
Should reams split open they should be re-wrapped or the packaging repaired and re-sealed.
Any distortion of the paper by not keeping it flat for example will cause irreversible damage.
Allowing reams to overhang or be stacked indiscriminately can be a potential source of damage.
It is recommended that only paper to be immediately used is removed from its wrapper and any opened paper should not be left overnight in copier feeder tray.