ENWW Appendix C Print media specifications 115
Printing and storage environment
Ideally, the printing and paper-storage environment should be at or near room temperature, and
not too dry or too humid. Remember that paper is hygroscopic; it absorbs and loses moisture
rapidly.
Heat works with humidity to damage paper. Heat causes the moisture in paper to evaporate,
while cold causes it to condense on the sheets. Heating systems and air conditioners remove
most of the humidity from a room. As paper is opened and used, it loses moisture, causing
streaks and smudging. Humid weather or water coolers can cause the humidity to increase in a
room. As paper is opened and used it absorbs any excess moisture, causing light print and
dropouts. Also, as paper loses and gains moisture it can distort. This issue can cause jams.
As a result, paper storage and handling are as important as the paper-making process itself.
Paper storage environmental conditions directly affect the feed operation.
Care should be taken not to purchase more paper than can be easily used in a short time (about
three months). Paper stored for long periods can experience heat and moisture extremes, which
can cause damage. Planning is important to prevent damage to a large supply of paper.
Unopened paper in sealed reams can remain stable for several months before use. Opened
packages of paper have more potential for environmental damage, especially if they are not
wrapped with a moisture-proof barrier.
The paper-storage environment should be properly maintained to ensure optimum printer
performance. The required condition is 20° to 24° C (68° to 75° F), with a relative humidity of 45
percent to 55 percent. The following guidelines should be helpful when evaluating the paper's
storage environment:
● Paper should be stored at or near room temperature.
● The air should not be too dry or too humid (due to the hygroscopic properties of paper).
● The best way to store an opened ream of paper is to rewrap it tightly in its moisture-proof
wrapping. If the printer environment is subject to extremes, unwrap only the amount of paper
to be used during the day's operation to prevent unwanted moisture changes.
● Avoid storing paper and print media near heating and air conditioning vents or near windows
and doors that are frequently open.
