Mini-Encyclopedia of Papermaking Wet-End Chemistry
Part Two: Definitions and Concepts

Dry Line

The dry line is the location on a Fourdrinier paper machine forming section where the appearance of the wet web of paper changes abruptly. Before the dry line the furnish has a glossy, wet appearance. After the dry line the wet web appears dull. The optical change is related to the effect of fibers poking through the air-water interface. On a well-adjusted paper machine the dry line ought to be straight. Increased refining and lower freeness of the pulp tend to move the dry line in the direction of the couch. Chemicals that promote drainage tend to move the dry line in the direction of the slice.

Request from the webmaster: Our goals include brevity and accuracy. Hopefully we have succeeded with the first goal without sacrificing the second. Please let us know right away if you find an error or omition. Also, please indicate points that need a clearer description.


Home page Research opportunities Business opportunities Background information Links to wet-end chemistry E-Mail
This page is maintained by Martin hubbe, Associate Professor of Wood and Paper Science, NC State University, .