Deckle

The mould and deckle is dipped into a vat of water and paper pulp that has been beaten (fibrillated).

The pulp is quickly scooped out of the vat and the mould and deckle is shaken as excess water is drained off.

If the paper slurry gets under, or if long fibers settles on top of the deckle, it will cause a more irregular edge.

[1]: 119, 177–178 Beginning in the early 1800s with the invention of the Fourdrinier machine, paper was produced in long rolls and the deckle became mostly obsolete.

Since some materials have a tendency to neck in or spread out after leaving the die, workers may need to adjust the deckle position to achieve target width.

This image shows red pigmented flax fiber on a hand paper mould, still contained by a deckle. This sheet is quite thick which is why there is fiber spilling onto the deckle. Next it is couched onto felts and pressed.
A hand-made piece of flax paper that has been pressed, but has not dried yet.
Deckle edge