Pulling a sheet from an algae-fiber vat is procedurally similar to standard Western hand papermaking — mould and deckle, vat, couch — but the physical behaviour of the slurry differs in ways that require deliberate adjustment. The key variable is the mucilage fraction: polysaccharides released from brown and red algae form a viscous matrix that slows drainage, alters fiber orientation during the draw, and changes how the wet sheet transfers to the couch felt.
Vat Preparation
The vat should be filled with enough water to allow the mould to move freely in all horizontal directions with at least 5 cm clearance on each side. Water temperature matters more with algae slurry than with cotton pulp: below 15°C, gel-forming polysaccharides become increasingly viscous and drainage can become impractically slow. Water at 18–22°C is a practical working range for Italian studio conditions in spring and autumn.
Stock Consistency
Algae-blend slurry is prepared at a lower consistency than cotton pulp — typically 0.8 to 1.5% by weight — because the mucilage increases effective viscosity beyond what the fiber concentration alone would suggest. A consistency that produces a clear glass of water with a faint milky haze when a small sample is held to light is a reasonable starting point.
If the vat feels sluggish and the mould is difficult to agitate, the stock is too thick. Dilute with additional warm water and re-stir from the bottom of the vat.
Formation Aid
Cotton-paper makers often add a formation aid (typically polyacrylamide or natural guar gum) to slow drainage. With algae pulp, the mucilage serves the same function — but it is uneven. Dense gel pockets from over-hydrated algae fronds create locally slower drainage areas, which show up as thick spots in the finished sheet.
Adding a small measured amount of guar gum (1–2 g per 10 litres of vat water) standardises the drainage rate across the entire vat, reducing the influence of random gel distribution. This produces more consistent sheet thickness without eliminating the characteristic slight translucency that algae fiber gives to finished paper.
Pulling the Sheet
The pull motion for algae-blend sheets is the same as for standard Western papermaking: the mould and deckle, held at a slight forward tilt, are lowered into the far end of the vat and drawn toward the maker in a single smooth arc, levelling off just below the surface before lifting.
Adjusting for Mucilage
The principal difference is speed. Cotton pulp drains through a wove or laid mould surface quickly, allowing the maker to shake the mould side-to-side immediately after the draw to align fibers. With algae slurry, initial drainage is slow enough that the window for shaking is wider — but the sheet can also move if the mould is tilted before the fiber layer has settled. The recommended practice is to hold the mould level for five to eight seconds before any lateral shaking.
The shake itself should be short and firm rather than continuous. Prolonged shaking in a high-mucilage slurry tends to push fibers to the edges of the deckle, thinning the centre of the sheet.
Drainage and Drip Line
A well-pulled sheet will drain steadily for 60 to 120 seconds before the drip from the underside of the mould slows to individual drops. If drainage does not slow within three minutes, the mucilage content of the batch is too high and the vat should be diluted further. Sheets that remain wet for extended periods on the mould are prone to tearing at the couch.
Couching
Algae-fiber wet sheets have lower initial wet strength than cotton sheets of comparable weight. The gel matrix provides some cohesion, but the fiber-to-fiber bonds have not yet formed. This means couching must be done with more care.
Felt Selection
Wool felts are preferred over synthetic alternatives for couching algae-blend sheets. The slight texture of wool felt creates micro-adhesion with the wet sheet surface that holds it in place during the rolling motion. Smooth synthetic felts tend to allow the sheet to slide, particularly at the leading edge of the couch.
Couch Motion
The mould is placed on the couch felt at one edge and rolled forward in a single continuous motion — not rocked or pressed repeatedly. A second felt is laid immediately over the freshly couched sheet before the next sheet is formed, building a post.
Pressing
Pressing removes free water from the post. With algae-blend sheets, pressure should be applied gradually. A single initial press at low pressure (a hand press tightened until it begins to resist) removes surface water without compressing the gel matrix. Waiting 10 to 15 minutes and pressing a second time at moderate pressure removes additional water and begins to consolidate the fiber structure.
Over-pressing — particularly in one sudden high-pressure application — compresses the gel layer into a skin on the sheet surface that resists subsequent drying and can cause surface cracking. Italian craft practitioners typically limit pressing to two stages over 20–30 minutes total.
Post-Press Handling
After pressing, sheets are peeled from the felts individually. Algae-blend sheets peel more slowly than cotton sheets due to residual gel adhesion. Working from one corner at a low angle, with one hand bracing the felt, produces clean separation without tearing.
Sheets that resist peeling are under-pressed and should be returned to the press for an additional cycle before attempting to remove them from the felt.
References
Technical documentation on vat formation and fiber drainage behaviour is available through the IAPMA. Photographic records of mould types referenced in this article are held in the Wikimedia Commons papermaking equipment category.