When weighing papers, manufacturers weigh one ream (500 sheets) of the paper's parent sheets. There for, 500 20" x 26" sheets of 24lb cover stock would actually weigh 24 pounds. The different parent sizes complicate things, but in the end, the weights do make some sense. For the vast majority of people who deal primarily with pre-cut 8 1/2" x 11" sheets, it is helpful to have comparable weights between the different paper grades. A table of the most common and useful stocks and their weights is listed below. Weights in the same row are very close or equivalent to each other.

Bond	Cover	Index	Text	Metric
20	28	42	50	75 gsm
24	33	50	60	90 gsm
28	39	58	70	105 gsm
32	45	67	80	120 gsm
38	50	77	100	140 gsm
43	60	90	110	162 gsm
47	65	97	120	177 gsm
53	74	110	135	199 gsm
58	80	120	146	218 gsm
65	90	135	165	245 gsm
72	100	150	183	271 gsm

Try our Paper Weight Converter to estimate other paper weights easily!

---

All About Paper

Picking out paper at the local department store is easy enough, considering that most of them stock only plain copy paper, along with the occasional stationery. However, when making the jump from white printer paper to the wide variety of papers sold by professional suppliers, many people are overwhelmed by the choices available. Paper types range from book to bristol to "onion skin," and their weights are even more confusing, considering that a sheet of 20lb cover paper actually weighs less than a sheet of 20lb bond paper! It is our hope that this article will clear up much, if not all, of the confusion created by the printing industry's unique system of paper types and weights.

---

Paper Types

The many different types of paper each have their own special characteristics, allowing printers to have a unique paper solution for any particular printing job. It is always helpful to know the differences between the many papers available, even if paper type is not important to your purchase. Below are listed the most common types of paper, along with a description of each.

BOND: This common paper is used in a wide variety of applications, from business forms to household stationery. It is a strong sheet used in most copiers and desktop printers in the form of 8 ½" X 11" 20lb standard copy paper. Another reason it is so common is that it absorbs ink well. This absorbency is due in part to the paper's cotton fiber content, which usually ranges from twenty-five to fifty percent. However, bond papers used in copy machines or fast laser printers usually lack this high cotton content because it can jam these machines easily.

BOOK: Aptly named, this paper is found mainly in books. It is well suited for two-sided printing and is very durable as well as relatively inexpensive.

BRISTOL: Originally produced in Bristol, England, this paper is a heavy, board-grade paper with a soft surface used, among other things, for catalog or paperback book covers. It is often manufactures by layering thinner papers together.

COVER: Cover paper, also known as cardstock, is a heavy, stiff sheet which folds and resists damage well. Because of its durability, it is very common, used for folders, business cards, greeting cards, post cards and cook covers.

INDEX: Index paper is stiff, inexpensive and absorbs ink well, making it the prime choice for index cards and business reply cards.

NEWSPRINT: Newsprint paper is used almost exclusively for newspapers, because it is recycled and cheap.

OFFSET: This paper is used in offset printing presses because of its ability to resist tearing in the large fast machines.

TAG: Tag paper is dense and strong, used for store tags.

TEXT: Text paper comes in many different colors and textures making it perfect for such applications as announcements and brochures.

SPECIALTY PAPERS: These include rice paper and the ultra-thin onion skin paper, also known as tissue paper.

The stiffness of paper depends mainly on the paper type. Most bond, book and text sheets are not very stiff. Tag and Bristol stocks tend to be stiffer, and index and cover stocks are made to be the stiffest. Stiffer papers are usually more durable and can be used for a wide variety of applications. Also, the grain of paper is often listed on the packaging. Paper is ultimately made from wood and has a grain just as wood does. The grain is simply the direction in which the fibers which make the paper tend to run. For example, 8 ½ x 11 paper packaged as having long grain, has fibers which run with the long edge of the paper. It is sometimes important to know the grain if you plan on folding the paper, because folding against the grain in a stiff sheet can cause the paper to crack. Many times, stiff stock that is meant to be folded, such as greeting cards, is pre-scored so it can be safely and easily folded.

Some papers may be available with a special coating which smoothes out the surface of the paper, reducing bleeding and making colors shine brighter. While several coatings are put on papers, ranging from clay to enamel, the most common is a heavy, high gloss chemical coating for specialized inkjet papers. This coating does not allow as much ink to soak into the sheet as would normally, so colors sit on top and look much better. Bond papers and cover papers are the prime candidates for this treatment, which can give a normal inkjet printout the boost it needs for true photographic quality.

---

Paper Weights - Advanced

As mentioned earlier, the system of paper weights used by the same printing industry can become quite confusing, considering that two different types of paper with the same basis weight do not actually weigh the same. This problem stems from the fact that each different grade of paper (bond, cover, etc.) has a different "parent size" for its sheets. Sheets of a particular paper grade are manufactured to this parent size and are then cut down to the more common sizes we use every day. Below are listed some of the more common paper types and the sizes of their parent sheets.

Paper Type	Parent Size
Bond	17" x 22"
Book, Text	25" x 38"
Bristol	22 1/2" x 28 1/2"
Cover	20" x 26"
Index	25 1/2" x 30 1/2"
Tag	24" x 36"

Simply look up any bond, cover, index, Bristol, or text weight and the weights in the same row are equivalent.

The measurement given in the final column of the table is the approximate metric weight of the paper. This metric weight is given in grams per square meter (gsm), which is the weight in grams, of one square-meter-sized sheet of paper. A measurement of 50gsm means that on square sheet, 1 x 1 meter, weighs 50 grams. The beauty of the metric measurement is that, unlike the standard pound-based method, it uses a standard sheet measurement (1m x 1m) for all values. Because of this simplicity, more manufacturers are listing the metric weights on their packaging. This allows for the concerned consumer to pick up a package of bond paper and a package of cover stock and realistically compare their weights without the confusion of the pound-based system.

Although the system of paper types and weights in the printing industry is complicated, it does make sense once some has a basic understanding of it. We hope this article answered all of your questions about this intricate system.

©2001 Desktop Publishing Supplies Inc.