Paper is very sensitive to changes in temperature and humidity. If paper is unloaded from a truck that has been in freezing temperatures and the paper is used immediately for printing (presumably in a heated room), problems will occur. When the paper is unwrapped in the warmer environment, it will absorb moisture immediately. Excessive moisture will cause flat sheet paper to curl, which creates feeding problems in sheet-fed presses (digital and conventional) as well as in desktop printers and copiers. The edges of roll paper for web-fed presses will become slack if excess moisture is present. Some of this moisture will disappear as the paper becomes warmer, but the edges of the paper will curl and stretch. This can cause severe paper feeding problems in a web press and the inability to maintain proper registration of the print.

Print producers should always order paper stock with enough lead time so that the paper has an opportunity to become acclimated to the temperature and humidity conditions of the printing facility. Paper should be left in its original wrapping and it should remain unopened until it becomes conditioned to the humidity and temperature of the pressroom. Many printing companies have temperature and humidity controlled environments to lessen the effects of changing environmental conditions. The time necessary for the paper to be conditioned properly will range from a few hours up to several days depending upon the quantity of paper to be used and the differences in the temperature and humidity levels between the pressroom and the environment where the paper had been stored previously.