In anticipation of discussing the various sizes of books (Trim Sizes), we are going to first take a look at how paper sizes differ throughout the world. As is typical of many things, two main standards exist in the English-speaking world: The US and everyone else. We’ll go over both and touch on the advantages and disadvantages of each. The size of a piece of paper is directly related to how easy it is to print and bind books, and that’s what our goal is.
US Paper Sizes
The origins of the sizes used in the US (and a few nearby countries) are lost to history, though there abounds quite a few different explanations, including the length of a vatman’s arms. (The vatman was the person in the papermaking process who collected the pulp onto frames before stacking and pressing, requiring very skilled labour.)
The sizes of papers in the US include Letter (8.5×11), Legal (8.5×14), and Ledger (11×17 or two Letter sizes together), producing at least two trim sizes: 8.5×11 (Letter) and 5.5×8.5 (Half-Letter). Typical use of the larger one is text books or tech manuals, often with a spiral binding, so they will stay flat when in use. The smaller one, also called Digest size, is close to typical paperback size, so it is one of the more popular used for shorter novels.
One of the big criticisms from other countries is that the Aspect Ratio isn’t constant with US paper. (Aspect Ratio is the mathematical comparison of the height to the width.) Letter has an AR of 1.29, Legal is 1.65, and Ledger is 1.55. Half-Letter has the same AR as Ledger because it is half and Ledger is double letter. (That’s just the way the maths works out.)
International Paper Sizes
The International Organization for Standardization (ISO, short for Greek isos meaning equal) has a set standard for paper sizes (ISO 216) based on an idea presented in 1786 by Georg Christoph Lichtenberg. He proposed using a constant Aspect Ratio, which mathematically works out to be the square root of 2 (√2=1.414…). The advantage there is that cutting a sheet in half or doubling it gives another with the same AR—very useful for enlarging or reducing prints.
Series A paper starts with A0, a sheet a full metre square, and each succeeding size smaller is exactly half the previous. Corresponding B sheets runs a bit larger, but each one is half way between adjacent A series sheets. The A series of paper is more common, and some manufacturers print books on A5 paper, only slightly wider and less tall than US Digest size (making them a bit stouter). You can often find books printed at the B5 size, only slightly larger than the US Trade paperback size (but again stouter).
That pretty much covers all the main differences between paper sizes. We’ll see how that affects book sizes later.