Some printers mismanufacture books. Paper has a grain, just like wood. The paper in a book should have its grain oriented vertically—top to bottom. If the paper’s grain is positioned horizontally, the book will have a strange feel. It will not “roll” open and will tend to snap shut. Your customers and bookstore browsers will not know what the problem is, but they will sense that something is odd about your book. It will make them uncomfortable. Which means you may lose sales.
What’s the problem? Presses are designed to print books of certain sizes. Although 5.5? * 8.5? is exactly half of 8.5? * 11?, one press should not be used to print both these trim sizes. If the same press is used for both, the grain in one format will be 90 degrees off.
Some book printers try to make do by printing books in more than one size on one press because they have just one press for text, but this does not produce acceptable books for their publisher-customers.
Pick up a sheet of paper. Tear it. Now turn it 90 degrees and tear it again. The tear will be cleaner with the grain.
Pick up a book. Roll a page in each direction with your fingers. You can usually tell which way the grain is.
When you send your requests for quotations (RFQs) to printers, specify “right-grain printing.” Printers know the difference. Let them know that you know the difference.