Most common type of envelope printing fast drying process, suitable for screens of 65 - 85 lines. Least expensive printing process mainly for line type and simple logos. Sometimes used as window patch material, but losing popularity compared to the new poly - styrene materials which are more transparent and less sensitive to moisture. Glassine is biodegradable and recyclable. Grain - Direction in which most of the fibers lie in a finished sheet of paper.
Paper folds more easily with the grain.
It offers greater resistance to being torn across the grain, and demonstrates greater tensile strength in the direction of the grain. Gripper Edge - The leading edge of paper as it passes through a printing press or folding machine. Guide Edge - The side of a printed sheet from which copy registers left to right. Guide Marks - A method of using cross line marks on the offset press plate to indicate trim, centering of the sheet, centering of the plate. Gum - An adhesive made with a plant base to seal paper envelopes.