Pasteboard

Whisk 20 g of wheat flour into 100 ml of cold water until there are no lumps. Cold first — flour dropped into hot water seizes into knots that never disperse.

Add 200 ml more water, heat gently and stir constantly until the mix turns from milky to translucent and thickens — around 80 °C. That change is the starch gelatinising, and it is what makes the paste adhesive.

Cool to room temperature and strain through a sieve. Lumps in the paste become visible bumps in the finished board.

Cut four sheets of paper 20 mm larger all round than the finished board. The edges will not laminate perfectly and get trimmed off at the end.

Tear a scrap both ways: it tears straighter along the grain. Mark the grain on each sheet.

Plan the stack so each sheet's grain runs at right angles to the one below. Cross-grain lamination is what stops the board curling — paper expands more across the grain than along it, so opposing layers cancel the movement.

Brush paste over one full face of the first sheet, working from the centre outward. Thin and even beats thick — excess paste squeezes out and cockles the surface.

Lay the second sheet down at 90° to the first and smooth from the centre out with a folder or the flat of your hand. Any trapped bubble becomes a permanent blister.

Paste and lay the third and fourth sheets the same way, alternating grain each time. Four layers is the middle of the historical range; three to six was normal.

Sandwich the wet stack between two flat boards with blotting paper either side and weight it down. Change the blotters after an hour.

Leave it weighted for two days. Drying free rather than under load is the single reliable way to produce a curled, useless board.

Trim off the ragged margin with a straightedge and knife, cutting several light passes rather than one heavy one.

Rub the face down hard with a smooth stone, bone folder or the back of a spoon. Burnishing compresses the surface fibres and gives the smooth finish that a printed line needs.

Clamp a single sheet and then the finished board so 100 mm overhangs the edge of a table, and measure how far each tip droops. The comparison is the whole engineering argument for lamination, in one number.

Hold the board up to a lamp. If light passes, add a layer. For playing cards this was not cosmetic — a card you can read from the back is not a card, and later card stock added a dark middle layer specifically to defeat it.

The material behind the first mass-produced pictures. Most surviving fifteenth-century European playing cards are pasteboard of three, four, or up to six sheets glued together. The same material made bookbinding boards, pattern templates and later the mounts for photographs. It is the oldest engineered laminate in common use.

Flour and starch. Period paste was flour and starch cooked in water. It is cheap, reversible with moisture — a genuine advantage in conservation, where an old board can be taken apart — and it is also food for insects and mould, which is why old pasteboard is so often found damaged from the inside.

Grain, and why it curls. Machine and hand papers both have a grain from the way fibres settle. Paper swells across the grain much more than along it, so a laminate with all its layers running the same way bends as humidity changes. Alternating the layers puts the movement in opposition. The same principle became plywood four centuries later.

What changed with the machine. Nineteenth-century mills began making thick board directly on multi-cylinder machines, laying wet layers onto each other in one pass rather than pasting dry sheets. Hand pasteboard survived where the extra control was worth it, and it is still made that way for conservation binding and fine card work.