GCM 240 Chapter 6: GCM 240-Chapter6
30 Sep 2016
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Paper must be brought to pressroom temperature before opening so it doesn"t curl due to moisture loss. Paper should remain tightly wrapped until it is ready for the press and after printing to prevent waves. Hygroscope: measures the moisture content of a pile of paper relative to the humidity of the pressroom: determines if paper conditioning is needed. Temperature conditioning: the paper is not unwrapped until it reaches the same temperature as the pressroom. Sometimes, paper is stored in pressrooms: in this scenario, temperature conditioning is unnecessary. Other times, paper is stored in a warehouse: in this scenario, temperature conditioning is necessary because the temperature of the warehouse is different from the temperature of the pressroom. Wavy-edged paper: when the exposed edges of paper absorb moisture and becomes wavy: occurs when the press sheet temperature is less than the pressroom temperature.
