Paper is a hygroscopic material and its humidity should be controlled due to static electricity it produces. As the moisture content drops below 50%, static electricity produced due to paper increases. Electrical charge-discharge caused by static electricity may sometimes reach up to 50-60 cm. This means the discharge of a nearly 1.5 million volts of static electricity.
Especially in paper storages, the paper should be kept in the humidity range of 55-60% to prevent humidification or dehumidification process. The paper starts to humidify or dehumidify above or below these ratios and that leads to undulation and curling problems affecting paper workability before printing. It is not possible to naturally obtain the 55-60% humidity required at printing houses. Especially the high heat produced by the machines operating in the printing house results in the humidity in the environment to drop down to 15%. This gives rise to very serious problems such as physical changes in different parts of the paper and not overlapping colors in four-color printing.
At large newspaper printing houses, parts of large paper sheets stacked together that are in contact with air, especially the corners have a different humidity than the other parts, generally they have lower humidity, they are drier. This causes the paper to physically react different in terms of flexibility and fragility and results in ruptures during printing. This problem which causes significant business and production loss can only be avoided by precise humidity control.