Paper Stocks for Printing

20 Aug

When you take a printing job to a commercial printer, chances are your printer will ask you questions about the type of paper you want for your project. With thousands of available papers to choose from, how do you even know where to begin? Here are a few important things to keep in mind to ensure that you and your printer choose the correct paper for the job.

Grade

Although there are many grades of paper, most printing jobs are best suited for a paper which falls into one of five basic categories, called grades: bond, text, offset or uncoated book, coated book, and cover. Each grade has its own original purpose, appearance, and end use, as suggested by the its name. For example, bond papers were originally used to print bond and stock certificates; today the term refers to paper used for letterhead, photocopying, and business forms.

Text papers are known for their interesting textures and attractive colors. They are frequently used for announcements, booklets, and brochures.

Book papers are used for trade and textbooks as well as general printing. They are less expensive than text papers and are found in regular or smooth finishes. Books papers have a wider range of weights and bulk than text papers.

Coated papers are used when high printing quality is desired because the surface is smoother and allows the ink to sit on the surface rather than soaking into the paper.

Cover papers complement coated and text papers but appear in heavier weights.

Basis Weight

The basis weight of paper is the weight in pounds of 500 sheets of paper cut to the basic size for its grade. The basic size for bond paper is 17″ x 22″; text, offset and coated papers is 25″ x 38″; and the basic size for cover stock is 20″ x 26″. Five hundred sheets of a lighter weight 17″ x 22″ bond weighs 20 pounds; hence the name 20# bond. Each paper grade has a range of basis weights such as 16# – 32# for bond.

Caliper measures the thickness of paper. It is measured in thousandths of an inch and is referred to as point size. The caliper of paper is not related to basis weight as the thickness of the paper often times has no bearing on the weight of the paper.

Opacity

Opacity refers to how much or little can be seen through one sheet to the next. Opaque papers are usually a higher quality offset stock and are more expensive than a commodity offset. Opacity is an important consideration when printing books or other multi-sheet pieces. Let your printer know if you are concerned about show-through.

Brightness

Brightness is rated on a scale according to the percentage of a blue light wavelength reflected. Most papers reflect 60 – 90% of light and the closer the number is to 100, the brighter the paper. Brighter papers make colors appear more vibrant.

Color

Colored papers are created by added pigment to the pulp during the manufacturing process. Keep in mind that ink colors will often appear different on various colors of paper.

Finish

The surface of the paper (finish) will greatly affect the look of the printed piece as the finish determines how the ink lies on the surface of the paper. During the manufacturing process of paper making, the paper surface can be changed by calendaring, a process where paper is pressed between two rollers. The more calendaring the paper undergoes, the smoother the surface. Textures can be added to the paper surface during the manufacturing process as well and result in finishes such as Laid and Linen.

The surface of paper can also be affected by sizing and coatings. Sizing is a solution added to paper  during the manufacturing process to make it less absorbent. This helps the ink remain on the paper’s surface rather than soaking in. Coating the surface of the paper provides a smoother surface for the ink to sit on. Depending on the amount of light reflected, the coating will be called gloss, matte, or dull.

Grain

Paper fibers lie in a single direction called grain. Grain direction affects paper strength and flexibility and is an important consideration in folding and binding. Folding along the grain creates a cleaner fold, and binding books with cover and text grain running parallel with the spine makes for a stronger and more visually appearing book. Ask your printer to keep grain in mind when selecting a paper.

These are a few of the items to keep in mind when discussing paper stocks with your printer. Come back next week for suggestions on grades and weights of papers for various types of printing projects.

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