Printing companies share something in common. For the most part, they all put ink on paper. Knowing how to communicate your paper needs will go a long way in helping you get the results you expect from your printing services, whether you’re working with catalog printing companies, large format printing services, or book printers.
The Difference Between Text and Cover Weights
Why do 80# text and 80# cover stock feel so different but have the same basis weight?
Clearly it is prudent for paper manufacturers to distinguish between text and cover weight paper. Multi-page publications often contain both. But the weight equivalence can easily confuse you—until you realize that cover stock and text stock are measured from different sized sheets (known as different “basic sizes”).
First of all, what exactly does “80# text” mean? It means that 500 sheets of 80# text paper will weigh 80 pounds.
Text stock has a basic size of 25” x 38”, while cover stock has a basic size of 20” x 26”. Therefore, for a stack of 500 sheets of 20” x 26” paper to weigh as much as an equal number of sheets that are 25” x 38”, each sheet of the smaller sized paper has to weigh more. For this to happen, each sheet must be thicker (actually almost twice as thick).
To add further complexity to this concept, keep in mind that it is only for the weight measurements that the 20” x 26” cover stock and 25” x 38” text stock basic sizes are used. Paper comes in other sizes as well. For instance, a printer can buy 28” x 40” stock for a 40” wide printing press. The extra width of this press sheet will allow him to take advantage of the two extra inches in the width of the press.
Regardless of the actual size of the paper the printer loads into the press, the weight of the paper depends on the weight of 500 sheets of the chosen stock at the basic size: 20” x 26” or 25” x 38”.
What About Papers Other Than Cover and Text Stock?
Let’s expand the field. Not all paper is text or cover. For instance, printing companies can buy index, tag, bristol, or bond paper. Each of these is usually measured in pounds, just like text and cover stock, but their basic size is different: 25.5” x 30.5” for index, 22.5” x 28.5” for tag, 22.5” x 28.5” for vellum bristol, and 17” x 22” for bond paper.
What About Points?
Another paper measurement system is used for some kinds of paper: points, or thousandths of an inch. This reflects thickness rather than weight. For a business reply card, for example, you would specify 7pt. stock (.007 inch)–if the card is small–and 9pt. for larger cards (based on US Postal Service requirements). Cover weight stock (for book covers) is also sometimes specified by thickness rather than weight. For instance, you might request 10pt., 12pt., or 15pt. C1S (coated-one-side) or C2S (coated-two-sides) stock depending on how stiff you want the cover of your perfect-bound book to be.
How About Metric Paper Measurements?
Finally, to add even further complexity, some paper companies state the weight of their papers in metric system measurements. This may be due to the increasingly global nature of the paper market and the fact that most countries other than the United States use the metric system. Look for “gsm” (grams per square meter) in the paper sample books.
Take the time to learn about your paper options. Knowing how to communicate your paper needs in a language printing companies understand will go a long way in helping you get the results you expect. This particularly holds true for traditional book printers, on demand book printing services, and catalog printers, since they often consume a larger amount of paper in their operations than commercial printing companies.
This entry was posted
on Tuesday, May 31st, 2011 at 1:45 am and is filed under Paper and finishing, Printing.
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