Foundations in Graphic Communications: Checking Color Proofs

New York City College Of Technology
Advertising Design & Graphic Arts: NYCCT

The Course At A Glance


Foundations in Graphic Communications
Patrick Henry     (p) 718.847.9430     (c) 917.647.0590     (e)


• Paper is made from fibers of cellulose. The most common source of cellulose is trees, but cellulose from cotton, hemp, and many other materials can be used.

• Cellulose from trees contains lignin: "brown stuff" that must be bleached and rinsed out to make printing and writing papers.

• Bleaching can leave traces of acid, which is what causes paper to turn yellow and crumble with age. "Acid free" papers contain no acid residue and last much longer.

• Cellulose fibers are separated from wood chips by washing, cooking, and bleaching. The pulp stock (a.k.a. "furnish") that remains is 99 percent water.

• In the papermaking machine, the stock is sprayed onto a long, wide, moving screen called a "wire." Water drains through the wire, and the pulp fibers begin to bond together in a very thin mat on the top side of the wire.

• The fiber mat is then squeezed between felt-covered press rollers to absorb more of the water. At this point the "paper" on top of the wire is still about 60 percent water.

• The wet paper is heated and dried by passing through a series of steam-filled metal cylinders. Heating and drying the wet sheet seals the fibers together and turns them into finished paper.

• The paper is run through a series of smooth-surfaced, chilled metal cylinders known as the "calender." The calender presses the drying paper smooth and uniform in thickness.

• "Supercalendering" the paper through an additional set of rollers gives more smoothness and adds gloss.

• Sometimes the paper is coated with a fine clay (kaolin) to fill in surface irregularities. This makes the paper brighter, more opaque, and easier to print on.

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