Like other production decisions, choosing paper (also referred to as “paper stock” or just “stock”) affects the cost and aesthetic value of your book. When selecting paper, professional print buyers consider basis weight, thickness, color, finish and other factors in addition to cost.
Overview
Paper Density, or Basis Weight
Paper Thickness, or Caliper
Paper Opacity
Coated vs. Uncoated Papers
Paper Finish
Paper Color
Freesheet vs. Groundwood Papers
Recycled Papers
Paper and Archival Quality
Why You Should (Almost) Always Use Your Book Printer’s House Stocks
When Not to Use Your Printer’s House Stock
Book Paper Selection Guide
Text Inserts, or Image Galleries
Paperback Cover Stocks
Dust Jacket Stocks
Hardcover Case Stocks
Endsheet Stocks
Overview
Like other production decisions, selecting paper (also referred to as “paper stock” or just “stock”) affects the cost and aesthetic value of your book. Professional print buyers consider the following qualities when selecting paper stocks:
Paper Density, or Basis Weight
The density of paper is expressed by basis weight. Basis weight is the weight in pounds of 500 sheets of the paper at a standard sheet size, which in the case of book papers is 25″ x 38″. For uncoated book papers, 50-lb., 55-lb., and 60-lb. are typical basis weights. Common coated stock basis weights are 70-lb., 80-lb., and 100-lb. In Asia and Europe, metric grammage is used instead of basis weight; instead of pounds, the unit is grams per square meter (gsm). By way of comparison, for text paper 60-lb. is roughly equivalent to 89-gsm.
Basis weight changes directly affect the weight of a book. A book printed on 60-lb. stock will weigh about 20 percent more than the same book printed on 50-lb. stock when the weight of the cover is factored out. Using 60-lb. stock instead of 50-lb. would therefore increase the cost of shipping cartons of the book. It may also increase the postage cost for shipping individual orders, depending on whether or not the weight of an individual copy is pushed into the next postage rate tier.
Basis weight also affects the thickness (caliper) of paper, although other factors enter into this as well, such as the method and amount of calendering used in the manufacture of the stock.
Paper Thickness, or Caliper
The thickness of paper is called caliper. Caliper is important because it determines the width of the spine of a book, and therefore the precise layout of the cover. Caliper is measured in pages per inch (PPI). The thinner the paper, the higher the PPI. For example, a 600 page book on 300 PPI paper will be 2″ thick, excluding the thickness of the cover (600 / 300 = 2). A 240 page book printed on 360 PPI stock will be .66″ thick, excluding the cover (240 / 360 = .66). The thickness calculated this way is often referred to as bulking.
Book paper should be consistently manufactured from batch to batch to a specified PPI, because the thickness of the paper determines the width of the spine. If the PPI changes significantly between batches when the book is reprinted the width of the cover spine will have to be changed to fit the altered bulking. This will take time and money, and may require another proof cycle, losing more time and introducing the potential for error.
Some uncoated stocks are manufactured to be thicker relative to their weight than standard stocks. These are called “high-bulk” stocks. High-bulk stocks are used to keep the weight and cost of the paper down while maintaining the same spine width as a the heavier stock. For example, a 50-lb. high-bulk stock is 456 PPI, almost the same as a standard 60-lb. stock at 436 PPI. A book printed on the 50-lb. high-bulk has almost the same thickness as if printed on the 60-lb. stock, but weighs about 17 percent less.
Here’s a list of typical uncoated digital book paper calipers:
- 50-lb. natural high bulk, 456 PPI.
- 60-lb. natural trade book, 436 PPI.
- 80-lb. white opaque smooth, 382 PPI.
Papers used for books with very high page counts, such as bibles or fat computer manuals, are especially thin. Some have up to 1560 PPI.
Your printer can provide the PPI of the paper you are using to print your book for the purpose of estimating spine width. They should also routinely provide you with a detailed cover layout template for each book you print, based on the page count of the book, the text paper selected, and the cover materials selected. This template will show all measurements for the spine, front cover, back cover, and bleed, and includes an allowance in the spine width for the thickness of the cover. For dust jackets, the template will also show flap dimensions and all-important allowances for where the dust jacket wraps around the hinges and foreedges of the case. Follow these templates accurately and it is the printer’s problem–not yours–if a cover or dust jacket doesn’t fit. Provide an inaccurate cover layout and it is your problem.
Opacity
Translucency in book papers is not good: It looks bad to have type or images on the back side of a page show through. Therefore, book papers are rated on opacity. Good book papers have high opacity. Opacity is governed by the caliper of the paper and the amount of pulp and fillers used in its manufacture.
Coated vs. Uncoated Papers
Papers are generally divided into coated and uncoated types. Coated stocks have been coated with materials to increase opacity, smoothness and ink holdout when printed on offset presses. The materials used include naturally white minerals such as Kaolinite–the clay used to produce porcelain ceramics–or calcium carbonate, plus binders. Coated stocks are used in offset printing where high-quality image reproduction is required; on digital presses, reproduction may be better on smooth uncoated stocks. Coated stocks often come with different finish options–glossy, matte, or dull–which affect the reflectivity of the page. Coated stocks are heavier than uncoated stocks with the same amount of fiber because of the weight of the minerals used in the coating.
Commonly used EVA binding glues don’t stick to coated stocks as well as they do to uncoated stocks, where they can permeate the fibers of the paper. Solutions are to use high quality opaque uncoated stocks–which may be preferable on digital presses anyway–or use a binder set up with PUR glue instead of EVA when binding coated stocks.
Paper Finish
As mentioned above, coated stocks are available in gloss, matte, and dull surfaces. Uncoated stocks used for book printing also vary in their surface finish, ranging from very smooth to vellum, which has a fine “tooth.” For digital printing, the smoother the better. Novelty finishes such as “laid” or “cambric,” which imitate handmade paper and fabric respectively, are almost never used for printing the text of books because of expense and printing quality issues. However, hardcover case cover materials–paper or synthetics–are readily available in different finishes, often imitating the texture of more expensive real-cloth materials.
Paper Color
Papers used in printing books typically come in shades of white or natural. Natural refers to cream-colored (as opposed to bright white) stock. Natural uncoated stocks are the standard for quality nonfiction and literary trade paperbacks. Natural stock connotes quality, and is reputedly easier on the eyes when reading for extended periods. Within the natural stock category, each type varies in shade, from light off-whites to darker cream colors. Ask for a sample from your printer.
White uncoated stock is used for illustrated books, textbooks, and within the trade paperback category, professional, self-help and how-to books. Coated stocks are mostly bright white, though each type varies in brightness. Some coated stocks are available in a light cream color.
Freesheet vs. Groundwood Papers
Paper is manufactured using either the freesheet or groundwood process.
Groundwood is made of pulp created by mechanical grinding, which results in more impurities and coarser fibers. The impurities severely reduce the longevity of the paper. Groundwood is used in books where low cost is an absolute imperative, such as mass-market paperbacks. Groundwood is almost never used in digital book printing, because its dustiness causes maintenance problems and decreases the life of digital presses.
Freesheet paper is manufactured with a chemical process that leaves it nearly “free” of impurities such as resins, lignin and groundwood fibers. It has a better finish and much longer life than groundwood stock.
Further information about paper longevity is available at the Gladfelter Paper website.
Recycled Papers
Paper is primarily made of wood fibers obtained by cutting down trees or using scrap wood. In addition, papermaking has always incorporated recycled fibers in the form of mill waste and scraps. Paper labeled recycled, however, incorporates recycled fibers from other sources such as discarded post-consumer waste. These post-consumer materials typically have to be de-inked before they can be used in making new paper.
Book papers with recycled content vary in price, availability, and printability. Generally, but not always, recycled stock is sold at a premium compared to regular stock, because obtaining the post-consumer fiber costs more than other sources of fiber. Recycled paper often has small flecks of color or other materials which may affect the appearance of the stock in a minor way.
It has been well documented that recycling paper reduces waste in landfills, saves forests, saves energy, and substantially reduces air and water pollution compared with using virgin pulp from cutting down trees. According to the EPA, recycling one ton of paper saves enough energy to power the average American home for six months, saves 7,000 gallons of water, and reduces greenhouse gas emissions by one metric ton equivalent.
Paper and Archival Quality
In the 19th century, when advances in typesetting, printing, papermaking, and cheap rail transportation enabled a mass market for books, many books were printed on groundwood paper. In the early 20th century, it was discovered that these books were falling apart on library shelves: the acidic impurities in the groundwood literally caused the books to self-destruct. Book papers were improved by the free sheet manufacturing process, which reduces acidic impurities from the pulp. In addition, printers began to use alkaline buffers such as calcium carbonate to create an alkaline reserve within the paper, so that any remaining acidity was neutralized. Today, all quality book papers are “acid-free,” so that libraries and other purchasers can be assured that books will not self-destruct on their shelves.
Why You Should (Almost) Always Use Your Book Printer’s House Stocks
Book printing is an extremely competitive business. A very large part of the cost of printing a book is the cost of the paper used, which the printer does not make and has to purchase from paper mills. Printers buy very large quantities of paper in order to get the paper at the lowest possible cost. The savings are passed along via lower prices resulting from a competitive marketplace.
Also, the papers that a printer keeps as their house stocks have been thoroughly tested and used for printing hundreds of titles: the printer knows that the paper prints and binds well. Book printers that use digital presses in particular have to be selective about what papers they use, as digital presses do not print well on many stocks with which offset presses have no issues.
Most book printers have a good selection of all types of papers commonly used for book printing.
When Not to Use Your Printer’s House Stock
If you are a giant publisher, you can sometimes save money by purchasing paper by the truckload for a series of books.
While furnishing text stock to a book printer is a dubious proposition (with the giant publisher exception above), furnishing preprinted covers or special cover stocks can sometimes enable a unique creative element for a particular book. In these cases, success requires close collaboration with the printer, and you will likely be responsible for cover printing or binding problems, as the materials provided are produced outside of the printer’s control.
Book Paper Selection Guide
Note: all papers listed are freesheet (permanent), unless specified as groundwood.
| Book category | Digital Press | Offset Press |
|---|---|---|
| Trade fiction and literature | • 50-lb. high-bulk uncoated, natural • 55-lb. uncoated, natural • 60-lb. uncoated, natural |
• 50-lb. high-bulk uncoated, natural • 55-lb. uncoated, natural • 60-lb. uncoated, natural |
| Trade nonfiction (history, public affairs, biography, etc.) |
• 50-lb. high-bulk uncoated, natural or white • 55-lb. uncoated, natural or white • 60-lb. uncoated, natural or white |
• 50-lb. high-bulk uncoated, natural or white • 55-lb. uncoated, natural or white • 60-lb. uncoated, natural or white |
| Other trade nonfiction categories (self-help, computer books, guidebooks, etc.) |
• 50-lb. uncoated, white • 55-lb. uncoated, white • 60-lb. uncoated, white |
• 50-lb. uncoated, white • 55-lb. uncoated, white • 60-lb. uncoated, white |
| High quality illustrated books (art, photography, etc.) |
• 70-lb uncoated, white opaque • 80-lb uncoated, white opaque • 100-lb uncoated, white opaque |
• 70-lb coated or uncoated opaque • 80-lb coated or uncoated opaque • 100-lb coated or uncoated opaque |
| Other illustrated books (how to, textbooks, etc.) |
• 60-lb uncoated, white opaque • 70-lb uncoated, white opaque |
• 60-lb uncoated, white opaque • 70-lb uncoated, white opaque |
| Mass-market format | • Not recommended. | • Groundwood, various weights |
Text Inserts, or Galleries
Often a book contains a handful of images in a sea of text. Those images can be laid out in special sections of the book called inserts or galleries. The inserts are printed on stock chosen to best reproduce the images–often a heavy coated or opaque white stock–while the text is printed on stock ideal for reading, such as a 60-lb. natural uncoated. Because the insert can be printed in full color while the body of the book is printed in black only, this can result in substantial savings over printing the whole book in color on the heavy coated stock. It also reproduces both text and images on their respective optimal stock. Offset printers, because they print in signatures of 4, 8, 16 or more pages, have limitations in the placement of inserts. Digital printers, because they print in single leaves of two pages each, can typically place an insert anywhere in the book. Multiple inserts can be bound into a single book.
Paperback Cover Stocks
Paperback covers are printed on stock that is coated only on one side, called, reasonably enough, “coated one side” or “C1S.” The outside of the cover (the printed side) is coated to provide a good surface for color printing, and the inside is uncoated to provide the optimal surface for binding glue adhesion. Caliper (thickness) of these stocks is measured in points: one point equals 1/1,000″. For most page sizes a 10-pt. C1S is an economical, high-quality choice. Larger page sizes–8″ x 10″ and above, and especially landscape format books–put much more stress on the cover. For these, use thicker 12-pt. C1S, or in extreme cases, 14- or 15-pt. C1S. Note that film lamination adds critical durability and tear resistance to paperback covers; UV coating and press varnish do not.
Dust Jacket Stocks
Dust jackets are typically printed on C1S or C2S stock in the 80-lb. to 100-lb. basis weight range. As with paperback covers, the bigger the page size the more handling wear and tear occurs to dust jackets. The rule, therefore, is to use heavier dust jacket stocks for larger books. Film lamination is also as critical for durability for dust jackets as it is for paperback covers.
Hardcover Case Stocks
Hardcover cases can be covered with a variety of materials (paper, cloth, leather, etc.), and a range of finishes (smooth, cambric, fake leather, etc.) and colors. Your printer can provide samples, typically paper cover materials in various colors and finishes.
Endsheet Stocks
The endsheets are the folded sheets of paper at the front and back of a hardcover book. They are the hinges that attach the case to the book block. As such, they have to be strong and are typically an 80-lb. stock. “Matching” endsheets are the color of the stock chosen for the text. Otherwise, endsheet stocks, like case cover stocks, are available in a huge range of colors. Endsheets can also be printed in either color or black and white; printed endsheets are one of the ways that a hardcover book can be dressed up.