Paper weight plays a large role in how your printing project will ultimately look and feel. The obvious heaviness of a laminated book cover paper is in stark contrast to the seeming featherweight of some book pages that appear to be almost see-through. But for most books and printed materials, the difference in the paper weight or thickness of the paper used is less obvious.
Authors typically select a thin paper for the inside pages of a book and a more substantial one for the covers, but choosing the right paper weight to use can be confusing. Some paper appears to be described in paper weight and others through a description of paper thickness. So how is paper measured and how can you tell what kind of paper to use?
Let’s look at the relationship between paper weight and thickness and how those contribute to selecting the right paper for your printing project.
Types of Paper Weight Measurements
Four types of paper measurements are commonly used. Two measurements describe the physical thickness of the paper, the mic and the pt, while the other two measure paper weight using gsm and pound.
Measuring by Thickness
Paper by its very nature is too thin to measure its thickness visually. But these two types of paper measurements look at the physical size of a sheet of paper to describe its thickness in either microns or points.
mic (microns): The micron unit of measurement is used mostly for papers that are extremely thin and not commonly used by printers in the self-publishing industry. A single micron is one-thousandth of a millimeter, and a paper that is measured at 10 mics, for example, would come out to ten-thousandths of a millimeter in size.
Paper that is measured with this very tiny unit of measure is typically only appropriate for paper stock that might be used for specialized industrial or scientific purposes rather than commercial ones.
pt (points): This thickness measurement unit is not commonly used in commercial printing or publishing situations, but it does provide a highly accurate physical representation of how thick a paper material is. Points are measured with a highly calibrated scientific instrument to determine the thickness of a material down to the one-thousandth of an inch.
Materials that are given a point value of 12 pt, for example, would measure at twelve-thousandths of an inch thick. While the point scale is an extremely precise method to determine how thick a paper or other material may be, the measuring instruments are not commonly used, and therefore the description of paper by its point value is also not as widespread as other measurement methods.
Measuring by Paper Weight
The other way to measure a paper is by evaluating its physical weight. But the weight of a paper is also usually a good indicator of the paper’s thickness as well. The thickness of some materials is greater than others, however, when the construction of the material is considered. As a result, some materials that are measured with gsm may be thicker than others that are measured through pounds simply due to the materials that make up the paper’s fibers.
gsm (grams per meter): Wood pulp manufacturers work with very large quantities of raw materials and because of that, they use the gsm or grams per meter measurement designation to help indicate the variations in materials made with wood pulp that can be very thick or quite thin, depending on how much of the wood pulp is pressed out. Unique to this measurement method, the gsm weight is determined by measuring the total grams of a piece of paper that is one square meter in size.
The pulp is rolled out and pressed into sheets before being cut down to size. This uniformity makes comparing papers with gsm simpler than other methods, because every paper weight and thickness are directly proportional to the size. Each paper sheet will be the same size, but those with a larger concentration of pulp have been pressed less and they will have a larger gsm. A paper with a higher gsm will necessarily be thicker due to a large concentration of wood pulp in the paper still remaining.
Conversely, the thinner paper will have less pulp and as a result, will have a lower gsm. In addition, this unit of measure is more commonly seen in the UK where the gram is a standard measurement over the US’s use of pounds.
lb (#/pounds): The most common way to measure paper thickness is measured in pounds or lb and this method of describing paper thickness is an “imperial” method that is most commonly used in the US’s paper industry. This weight determination is made by weighing a stack of 500 sheets of paper, called a ream.
The weight of the ream determines the designation, but most paper stock is between the weights of 20 and 140 lbs. Once a ream of paper stock exceeds 50 lbs, it may be referred to as card or card stock. This heavier-weight card stock is also usually thicker as well, just like papers with a high gsm designation, since heavier paper usually has a higher concentration of pulp in it.
But since the pound unit of measure is a commonly used term used to describe everything from how much someone weighs on a scale to the amount of air we put in a car’s tires, talking about a single sheet of paper as being “40 pounds” might seem strange and confusing. But since an individual sheet may be referred to as “30 lb” or even an astonishing “140#” paper, the key to translating this paper weight and thickness measurement is to remember that it is referring to the total weight of a ream of paper.
Are Heavier Papers Always Thicker?
Unfortunately, thickness and weight are not always directly proportional to each other. A lot goes into the manufacturing and refining of paper as it transitions from its initial form of pulp. And of course, some papers have other ingredients included in them, however slight, that may impact the weight and therefore the thickness of the paper.
As a general rule, however, heavier papers are mostly thicker, but there are always exceptions. But using heavier-weight stock or even cardstock and expecting it to be thicker, even marginally so, than stock with a lower pound or gsm designation is generally an acceptable guideline to go by.
Why Paper Weight Matters
Some printing projects require a sturdier paper, so self-publishing authors who have unique or special requirements will want to be educated on the differences between the thick and thin paper stock that their printer offers. Some applications, like lamination, gloss, foil stamping, or even die-cutting on a book cover will need to be completed with strong, thick paper.
The exterior pages of a catalog or other multiple-use books will also need to be crafted with thicker paper that will not only withstand repeated usage but will also look great with the high-gloss coating that is so popular with that type of printing project. Interior pages of a novel, by contrast, may typically be constructed with a very thin paper that may not need to withstand heavy use like a book cover or magazine cover might need to.
In addition, thinner papers are also less bulky, so they are typically used in book construction to avoid overly lengthy projects. And self-publishing authors also may consider how cost plays into the equation when choosing a lighter or a heavier paper weight for their book, since thicker paper tends to cost more than thin paper options.
Another benefit of using lighter paper weight in a printing project, when it is appropriate, is that it ultimately will cost less to distribute the books and deliver them due to the overall relative weight of the book.
Choosing the Right Paper Weight for Your Project
Understanding how paper thickness and paper weight relate can help authors who are self-publishing their work, because they can make the optimal paper selection for their project so it will look great once it is printed. But working with a trusted printing partner like Dazzle Printing can help writers navigate the myriad of paper weight choices they are faced with, too.
The professionals at Dazzle Printing help authors make the right selection for their printing project so that their hard work and design elements will look exactly how the author intended and the paper choices will complement the book’s design without detracting from the overall look and feel of the book or project. When decision which papers to use for your printing project, we strongly recommend that you send for our free sample packet. Not only does the packet contain samples of our four binding styles (perfect bound, plastic coil, saddle stitch, and wire-o), but the plastic coil contains samples of all of our paper options.
Because self-publishing your own work comes with so many more steps than just simply writing the content of your project, working with a trusted printing company is the best way to help you turn your concept into a beautifully printed project with perfectly selected paper choices.