Paper and board curl before printing
Substrate curl is the sheet moving on its own. Moisture, grain direction, and a coating on one side are the usual drivers. This is separate from curl that a laminator puts in.
Checks
- Acclimate wrapped stock in the pressroom before you open it. A cold ream opened in warm air curls as it takes on moisture.
- Note which face curls. A one-sided coating or a moisture difference between faces pulls that way.
- Run grain in the direction the press and the folder expect. Cross-grain sheets grow more across the width.
- Keep opened piles covered. An uncovered stack curls at the edges first.
Materials in the directory
Compare coated paper, uncoated paper, paperboard.