Paper: Properties

  • Basis Weight: Weight in pounds of a ream (500 sheets) of paper cut to a standard size according to the grade of paper. Also called nominal weight.
  • Brightness: Reflective quality or brilliance. The brightness level of most white, uncoated papers is generally much higher than that of coated papers. A No. 1 sheet must have a brightness of 91 or above; a No. 2 sheet 87 to 90.9 brightness.
  • Bulk: Thickness, usually expressed as pages per inch.
  • Caliper: Thickness of paper expressed in "points" or thousandths of an inch. Also called bulk. Industry standards are plus or minus 6% from the target caliper.
  • Equivalent Weight: A comparison of the basis weights of two different sheet sizes of the same paper.
  • Finish: Surface characteristics, such as vellum, wove or laid finishes.
  • Grammage: Basis weight expressed in grams.
  • Grain: Direction in which the fibers in a sheet of paper have been made on a paper machine.
  • Lightfastness: Ability to resist fading or yellowing when exposed to light.
  • Opacity: The property of paper that minimizes ink showing through on the other side. Thick paper is more opaque than thin paper. Coated paper is more opaque than uncoated paper. Rough paper is more opaque than smooth paper. Groundwood paper is more opaque than free sheet paper.
  • Porosity: Property that allows air to permeate and allow ink to penetrate.
  • Sizing: A treatment for paper that gives it resistance to the penetration of liquids such as water.
  • Stiffness: Flexural stiffness is the ability of paper to withstand bending force. Handling stiffness is a paper's ability to support its own weight. Paper is stiffer cross-grain by a ratio of 2 to 1.
  • Substance: Weight in pounds of a ream of standard-size business papers. Similar to basis weight of other grades of paper.
  • Toothiness: The property of paper that allows it to take printing ink.