How paper is made

Thin the stock

Pulp is blended in the right ratio of hardwood, softwood or recycled fiber and diluted in tanks. Mills mix in whitening agents, fillers and chemicals that give the sheet strength or water resistance.

Beat the fibers

The slurry passes through a refiner that roughs up the surface of each fiber, which lets the fibers grab each other when the sheet forms.

Spray onto the wire

A headbox spreads the slurry across the full width of a fast-moving woven mesh. Less than 0.4 percent of what sprays out is fiber, and the rest is water, which drains through the mesh or is sucked out by vacuum boxes.

under 0.4% fiber

Squeeze between rolls

The wet sheet is carried on felts through the nips of heavy rolls that wring out more water. Leaving the press, the web is still more than half water.

Dry over hot cylinders

The sheet snakes around a long row of steam-heated cylinders that boil off the remaining water. It comes out with only about 6 percent water, the level it will keep in a room.

about 6% water

Size and smooth

A thin layer of starch can be rolled on to cut dust and improve how ink sits. Stacks of rolls called calenders then squeeze the sheet to make it smooth and even in thickness. Glossy grades get a coating of kaolin clay or calcium carbonate.

Wind and slit

The finished sheet is wound onto a giant reel, then unrolled and slit into narrower rolls or chopped into sheets of standard sizes like A4 and letter.