The storage and handling of paper is important because it helps to ensure free running on the press, particularly in the winter months. The following guidelines will help eliminate potential problems:

  • Allow the paper to reach temperature equilibrium within the press room environment before removing the ream wrappers or stripping the bulk packed wrapping. The mill packaging is specially designed to inhibit moisture penetration into the paper.
  • Cold paper opened in a warm room will cause a rapid increase in humidity around the stack, resulting in moisture pick-up which can cause paper distortion (wavy edges) or paper stretch.
  • Remember – temperature and humidity will fluctuate throughout the day and night (except in air conditioned rooms) and covering work in progress with moisture proof material at all times will minimize loss or gain of moisture in the paper. Stack covers are easily obtained or stretch wrap is as suitable. These precautions are even more important when printed work is for subsequent laser printing. As the temperature falls, the humidity will rise.
  • In an ideal world, press room conditions should be controlled at around 20C @ 45-50% rh

Guide to the conditioning times – time for paper to sit in the print room prior to opening wrappers:

Temperature Difference between Paper and Print Room

Volume (m3) Weight (kg) 5C 10C 20C 30C 35C

0.4 320 9 hrs 17hrs 36hrs 64hrs 92hrs

0.6 480 10hrs 20hrs 42hrs 76hrs 106hrs

1.0 800 11hrs 23hrs 46hrs 84hrs 115hrs

Paper designed for laser printing is made to very tightly controlled moisture content and as such, its storage and handling is very important. Such papers should be printed with a minimum of damping and with inks that can withstand subsequent passage through a laser printer. Keep laser printing papers covered or wrapped as much as possible as they are made to a lower moisture content and are more prone to moisture pick up from the atmosphere. There is nothing that can be done to remove wavy or tight edges, once this has happened it is unlikely they will flatten out again. Severe problems like this can make the render the paper useless, so it is vital the paper is not subjected to adverse conditions.