 modern deckle is produced by a purpose-built machine to give the appearance of a true deckle edge by cutting a smooth edge into patterns.Many modern readers are unfamiliar with the deckle edge and may see it as a defect; for example, Amazon.com has left notes to buyers that the deckle is not a flaw in the product.A deckle edge is unrelated to the practice of unopened pages, in which a reader must cut open pages with a knife.