Mould and deckle are fundamental components of bookbinding and papermaking, each serving unique purposes in the creation and preservation of books and documents.
Understanding the roles of these elements offers insights into the craftsmanship and history of the printed word. Let's delve into the world of mould and deckle, exploring their functions, mechanisms, and significance.
Mould: The Foundation of Papermaking
The mould is the backbone of papermaking, a fine mesh screen used to drain water and form the paper sheet. Typically made of wires stretched over a wooden or metallic framework, the mould has been evolving since its inception in the early 18th century.
Modern papermaking has introduced advances like the Fourdrinier machine, which uses a continuous wire belt instead of individual moulds. However, the basic principle and function remain the same: to create a uniform, flat surface for the pulp to conform to during the sheet-forming process.
Wire Moulds: Traditional Craftsmanship
Hand papermaking or 'pulp & paper' centrifugation still uses wire moulds. Craftspeople use dpi, or 'dips', to scoop pulp onto the mould for couching – transferring the formed sheet onto felts for pressing. The wire mesh size determines the paper's texture and surface qualities.
The Louette, Cordenons, and Khadi papers, for instance, retain their distinct textures due to the specific wire sizes and patterns used in their creation.
Cylinder Moulds: Industrial Efficiency
Industrial papermaking employs cylinder moulds – large, rotating drums covered in woven wire cloth. The cylinder dips into the vat, scooping up pulp, and then rotates over drainage boxes, allowing water to escape through the wire.
The size and speed of the cylinder determine the paper's basis weight and production rate. Large papermills might use cylinders reaching 10-15 feet in diameter, capable of producing tons of paper per hour.
The Deckle: Containing Pulp, Framing History
While the mould gives shape to the paper, the deckle, or 'coulter', contains the pulp and contributes to subsequent sheet irregularities. Usually crafted from wood or handmade paper, the deckle frames the sheet's edges, preventing pulp from spilling out during dipping.
The deckle's influence is evident in 'deckled edge' paper, bearing natural, jagged edges remnant of hand papermaking traditions. Its role has evolved from a functional necessity to an aesthetic choice in book arts and craft papermaking.
Deckle Frames and Subtle Edges
Hand papermakers replenish the vat periodically, using a deckle to scoop pulp onto the mould. Pulp levelled within the deckle's frame creates uniform sheets. To achieve a soft, suede-like edge, papermakers gently agitate the pulp within the deckle before dipping.
Stationery from brands like C rio & C ro, with subtle, irregular edges, showcase the deckle's impact on the paper's aesthetic.
Deckelkante: German Tradition Meets Industry
In Germany, the 'Deckelkante' remains a traditional tool, used in whetstone-style hand papermaking. The large, board-like deckle has notches on its side, allowing it to slide onto and off the mould's wire, without disturbing the forming sheet.
Today, some papermills, like Favini's 'Feelpaper' line, employ a modern take on the deckle. By lleno casting, they create sheets with Southdown sheep's wool fibres left uncut, giving a unique, natural edge to their paper.
From the traditional wire moulds in hand papermaking to the industrial cylinder counterparts, and from the wooden deckle frames to innovative German-inspired techniques, mould and deckle continue to shape and frame our printed world.