Grain direction

The direction in which all or most of the paper fibers are oriented in a paper sheet. Since the grain is produced on the forming wire of a papermaking machine in the direction of the web’s travel through the machine, the grain direction is also called the machine direction. The direction perpendicular to the grain direction is the cross-grain direction. Grain direction is an important factor of such paper properties as strength and dimensional stability.

Grain direction is very important in book printing. Grain direction in internal pages should run from top of page to bottom of page. This grain direction will allow the open book to be flatter. Grain direction of a paperback cover should be from left to right. This grain direction for the book cover, will help the book resist ‘curl’.

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Test the grain direction by tearing from two directions

PUBLISHING TIP  Grain direction is very hard to perceive. There is however an easy way to test if the page grain is correct. Simply tear the paper from the page edge. If the grain direction is top to bottom the tear will be quite straight. Tearing across the grain direction will produce a curved or crooked tear.