Paper Styling: Characteristics of paper

Opacity, bulk and substance

Some of the most important paper characteristics are felt more than seen. Opacity determines how well a sheet blocks light and prevents show-through, while bulk, caliper and thickness create a sense of substance without necessarily increasing weight. These properties influence readability, handling and the overall perception of quality.

These characteristics are verified throughout manufacturing. Caliper is measured to thousandths of an inch (or mils), opacity testing evaluates a sheet’s ability to block light and porosity testing measures how readily air moves through the paper—an important indicator of coating penetration, moisture movement and print performance. Together, these measurements help ensure every sheet delivers the intended balance of appearance and functionality.

Strength and performance

Beautiful paper also has to perform. Whether running through a high-speed press, folding into a carton or surviving the rigors of mailing, paper depends on carefully engineered mechanical properties. Stiffness, tensile strength, tear resistance, fold endurance, surface strength and fiber bonding all contribute to reliable performance throughout printing, converting and everyday use. Paper strength is every bit as important as its optical properties.

These properties are confirmed through a series of specialized laboratory tests. Tensile testing measures the force required to break a strip of paper, tear testing measures the energy required to propagate an existing cut, stiffness testing evaluates resistance to bending and porosity testing measures airflow through the sheet. Together, these tests allow papermakers to engineer papers that not only look exceptional but also perform consistently from the mill to the pressroom and ultimately to the end user.