Glossary of Terms

Basis weight: Weight per a selected unit of area of a grade of paper; grammage or "grams per square meter" is used throughout the world and scientifically in the United States; the United States uses many different weight designations, depending upon the type of paper such as Bond 17x22, Book 25x38 and News 24x36.

Equivalent basis weights
GSM 24x36 25x38 17x22 48.8 30 33 13 52 32 35 14 56 34 38 15 59 36 40 16 66 41 45 18 74 45 50 20 89 55 60 24

Caliper: Thickness of paper in thousandths of an inch and typically measured in points or mils.

Opacity: Sometimes referred to as "show-through," this is the property of paper that prevents print areas from showing through to the other side.

Pages per inch (PPI): Number of sheets that can be counted in a one-inch tall stack of paper.

Post-consumer waste: Material that has served its intended purpose as a consumer item and can be recycled into a new product.

Post-industrial materials: Scrap or waste produced during the manufacturing of virgin material.

Process chlorine free (PCF): Paper brightened without the use of elemental chlorine or chlorine compounds.

Recycling: Using materials recovered from the solid waste stream as raw materials in the manufacturing of new products.