Balance the relative humidity of the pressroom compared to the relative humidity of the paper to be printed. Relative humidity is a measure of how much moisture air or paper can hold versus how much it is actually holding at a given temperature.
Before printing a job, the printer must “cure” the paper by letting it sit, wrapped, in the pressroom for a determined amount of time. This will bring the paper to the same temperature and humidity as the pressroom, helping to prevent several printing problems. For instance, ink on cold paper takes longer to dry than ink on room-temperature paper.
Ink on dry paper may “chalk” if the dry paper absorbs the liquid in the pigment before the solid pigments adhere to the paper. Paper with too much humidity will expand, causing it to wrinkle on press. This can cause misalignment and a lack or registration in the printing. See also registration.