The way we identify paper here in the USA frustrates many people. Most of the world utilizes the metric system but here in the US, we use use a nomenclature related to the manufacturing process. After reading this article you’ll be able to differentiate paper by types, thickness, weight, application, finishing and use. You will be able to compare how paper in USA is identified elsewhere.
You will be able to answer questions such as “How is a 20# ( pound ) copy bond paper different from a 60# offset paper?”
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All About Paper Weights: Understand "Basis Weight", Bond, Book Grades, Text Grades, Cover Stock, Index and Tag.
("U.S. Basis Weight") is defined as the weight of 500 sheets of paper in its basic production size (parent size), before any cuts take place. Find the chart of paper manufacturing sizes on this same page.
- Example #1: Basis Weight of Bond Paper: A sheet of bond paper comes out a of production line and measures 17x22 inches. If the weight of 500 of those sheets is 20lbs, that bond paper will get to be identified and labeled as “20lbs”, or “20# bond”. When you cut the 17”x22” sheet into two, you will get 2 sheets each measuring 8.5”x11” which happens to be a “letter size”. Assuming that we have those 500 uncut sheets, we’ll end up with 1,000 sheets of 20# bond paper. Each group of 500 sheets then weights 10 lbs.
Conclusion: The Basis Weight of Bond paper is 20lbs.
If the same components to the paper and thickness were produced out of a sheet of paper that measures 25 x 38 inches, 500 sheets of that paper would weight 50 lbs. It would be a 50lbs basis. So as you can see, the paper, physically, would be the same one. But its name will be 50 instead of 20. The number itself is not indicative of how thick one paper is when compared to another one.
- Example #2 for 100 lbs coated paper: We will find out the basis weight of a coated sheet of paper. There is an illustration that helps visualize. Coated paper is manufactured in sheets of 25 x 38 inches. In this case, 500 of those sheets weight 100 lbs. Therefore the Basis Weight for this paper is 100 lbs, also known as 100# coated text paper.
Chart of Paper Manufacturing Sizes to determine Basis Weight Parent Sizes
Paper is manufactured at paper mills using different machines with different technologies.
Names and Sizes of Paper in the US Standard System
|Ledger||279 x 432||11 x 17|
|Legal||8.5 x 14|
|Letter||216 x 279||9.5 x 11|
|Monarch||7.25 x 10.5|
|Executive||140 x 216||5.5 x 8.5|
|Statement||108 x 140||4.25 x 5.5|
|Business Card||2 x 3.5|
The U.S. Standard System changes the proportions of the sheet once it is cut in half making it difficult to size up or down
The International Systems for paper weight and sizes is designed so that cutting paper in half still keeps the same proportions. That system is known as ISO "A"
The Grades of Paper are defined in terms of its use. Each grade serves a purpose:
- Opaques and Offset Papers
- Coated Papers
- Writing Papers (a.k.a. Correspondence Papers or Bond Papers)
- Text and Cover papers
Opaques and Offset Uncoated Papers: These are similar with some specific differences
Offset Paper: Typical basis weight for this paper are 50 lbs, 60lbs, 70lbs and 80lbs
- Vellum finish which is extremely rough
- Patterns: as in Laid and Linen finishes
Opaque Paper: The typical basis weights for opaque paper are 50 lbs, 60lbs,70lbs and 80lbs
- Film Coat
- Thin Coat
Coated Papers Have 5 types of Finishing and 5 Qualities
- Cast Coated, which are very shinny
Writing Paper, Correspondence Papers or Bond Papers
Text and Cover Papers
|US Basis Weights||Caliper||Metric|
|Bond||Text||Cover||Index||1 Point = 0.001"||GSM (g/m2)|