Most physical properties of paper undergo change as a result of variations in moisture content. Water has the effect of plasticising the cellulose fibre and of relaxing and weakening the interfibre bonding. The electrical resistance and the dielectric constant of paper both vary with moisture content. The absorption and reflectance of certain bands of infrared and microwave radiation by paper are affected by its moisture content. The amount of water present in a sheet of paper is usually expressed as a percent. The amount of water play an important role in calendering, super calendehng, printing and converting process. Moisture control is also significant to the economic aspect of paper making. Poor moisture control can adversely affect many paper properties.