When it’s time to pick a type of paper for your printed job, there are a lot of terms you might hear as you make your decision. From the obvious ( color ) to the obscure ( opacity ) or confusing ( weight ), there’s more to paper than you can see on the surface.
Category Because papers were originally created for a particular printing purpose, these categories of purpose still are used and affect other aspects of the type of paper (such as the weight). Some common categories are text, cover, index, newsprint, or bond. A more recently developed category is office paper.
Weight Have you ever noticed how your copier paper is called 20 pound, but even a cheap paper used by your offset printer is called 50 pound? This oddity results from the fact that office papers are weighed in smaller sheets than the papers used by offset printers…so a 20 pound copier paper really does feel like it’s the same weight as a 50 pound offset paper. You weren’t losing your mind.
Offset text papers are weighed in sheets that are 25” x 38”, while office paper stocks are weighed in sheets that are much smaller. So while a ream of each might weigh the same, the offset paper would would be labeled with a much higher weight. To complicate matters, cover stocks are weighed in sheets that are 20 × 26. So their weights are often the same as text weights, even though the cover weights are actually much heavier!
Here are some common equivalents:
Office paper 20 pound, offset text 50 pound
Office paper 24 pound, offset text 60 pound
Office paper 28 pound, offset text 70 pound
Office paper 32 pound, offset text 80 pound
100 pound offset text is pretty close in weight to 65 pound cover
Bulk This is the thickness of the paper. It is usually measured in pages per inch: a pile of paper an inch high is compressed, and then the number of pages in that inch are counted. Phone books have low bulk so that the book is as thin as possible; best-sellers usually have high bulk to make them look heftier than they really are. Imagine if the phone book were made with the same paper as a best-seller!
Opacity This is the ability of the paper to take ink onto its surface without allowing it to show through. There are two kinds. Visual opacity is the amount of light that shows through the paper (expressed as a percentage of opaqueness, such as 100 percent opaque). Printed opacity tells you about the ink “holdout“—the ability of the paper to keep the ink on the surface, rather than letting it sink in. This is expressed as high, medium or low printed opacity. Glossy, coated papers have very high printed opacity because they have a layer of clay on them that keeps the ink from sinking in. Some heavy, uncoated papers that resemble the papers used for watercolor painting have a low printed opacity. Newsprint, which has a medium printed opacity, has a high level of visual opacity and bulk for the cost.
Grain This is the direction in which the wood or other fibers line up in the paper-making process, as they travel down a conveyor belt (called the “wire” in the paper-making industry). The important thing to know is that paper folds and tears most easily with the grain. You can test for grain by tearing a piece of the paper. If it tears easily in a relatively straight line, you are going with the grain. If you can’t make it tear straight, you are going against the grain. Most office paper is “grain long” meaning the grain runs parallel to the long side of the sheet; this can make it messy to fold the paper in half, such as when you make a booklet.
Finish This is the treatment of the surface of the paper. It includes things that are done to the surface and things that added to the surface (such as a clay coating). One treatment that is often done is “calendaring” (pressing the paper, much like ironing, to smooth the surface). Another important treatment is pressing different patterns into the paper. Some common textures that result are woven, felt, eggshell, or linen (all are done on both sides of the sheet), as well as laid (which only appears on one side).
Uncoated paper has an uneven surface that absorbs ink, while coated papers hold ink on their smooth clay surface.
Coated papers can be glossy, dull or matte. Remember, while glossy finishes are good for photographic images because they reflect light most evenly, dull is best for reading text because it doesn’t cause glare. Also, it is usually a good practice to include a finishing clear coat (such as a varnish or aqueous flood) when using coated papers, so that the ink doesn’t pick up smudges or fingerprints.
Color There’s more to color than the Astrobright book! There is a wide range of whites, which result from differences in bleaching, as well as dyes that make paper into a rainbow of colors. Remember, though, you can’t print black or dark ink on darker papers and expect anyone to read it. You can, however, print white ink on dark paper or use foil stamps (whether metallic or not) and have it stand out from the dark background.
Paper Content Paper can be made from many different materials. Commercial papers are usually made from wood or cloth, although you can find rice, flowers, hemp, plastic and many other materials—even some that are made from recycled money! Cloth papers are called “bond” as a category and are often associated with quality, which results in their use for company letterhead materials.
The recycled content of paper is an increasingly important factor in paper content. Unfortunately, papers with a high percentage of postconsumer content tend to be more expensive than “virgin” paper sources. Some other environmental factors to take into account are the use of chlorine in bleaching, the presence of acid in the paper (which limit its shelf life and becomes important if you are creating a piece that has archival purposes) and, most recently, the availability of papers with Forest Stewardship Council certification.FSC certification means that the paper was made from wood taken from forests that have been sustainably managed.