What’s in a Name?
Growing up, my crazy uncle used to say “You can call me whatever name you like, just don’t call me late to dinner.” A clear name is important and I think of my uncle whenever someone asks me “Why does a paper change its name when used in different markets?” If you have had to purchase or spec printing paper, you know what I am talking about. A 20# Bond can also be called 50# Offset, 28# Cover, 46# Tag or 42# Index, but they are all the same caliper (paper thickness). We are born with a given name, or maybe a nickname, and are identified by it throughout life. Products are produced with a clear product name. Why would a paper be called up to five different names? It’s market driven, actually.
There are different printing “categories or markets” for which paper has been specially developed for decades and each one has its own specifications. Let’s start with the general “categories” in which they are used. There are:
- Uncoated Commercial Printing Papers
- Coated Commercial Printing Papers
- Fine Papers
- Specialty Papers
- Office and Consumer Papers
Within these markets, there are many different “grades” of papers, ranging from offset, cover, tag and index, to name a few. These paper grades, in most cases, define their use and can be manufactured differently for their durability. As there are too many to discuss in this blog, we will just talk about the most common:
- Bond papers were manufactured for the electronic printing market and have good erasability, absorption and rigidity.
- Offset papers are manufactured specifically for offset lithography to repel moisture when used with press dampening systems.
- Cover stock papers, also called card stock, come in heavier weights than their offset kin and are used for various printing projects, which require a thicker and more durable substrate, such as postcards, business cards and book covers.
- Tag stock is exactly that. This thick and durable paper was made for hanging and product tags.
- Index is a thicker stock, used for direct mail, postcards and index cards.
But what is really in a name?
All papers are named with a “weight” and “grade” (20# Bond). This “weight” naming convention seems to be a point of confusion for most. We explained above why paper grades used in different markets are called different names, but if it is the same “caliper or thickness,” why does the weight (#) in the name change? We can thank our paper manufacturers for this confusion.
A paper’s weight is not a factor of caliper or how much fiber it contains, but how much its “base sheet” size weighs. The U.S. paper industry measures paper weight of 500 cut sheets (ream) of its base sheet size. The base sheet size for each paper grade was determined by mill efficiency to manufacture the traditional sheet sizes required for that print market. Even though traditional print sizes have changed over the years with different printing technology, these base sheet sizes have stayed the same.
As you can see below, each paper grade has its own base sheet size:
To add a little more confusion to this subject, a base sheet size other than 17x22˝ can be also calculated in 1,000 sheets rather than 500. When this calculation is used it is noted as weight per 1,000 or #M.
It should now make a little more sense that an Offset and a Cover stock, which have the same caliper thickness of 116.63gsm, would be named 81# Offset and 45# Cover as the base sheet size of the cover is much smaller so less paper mass is being weighed.
Remember the noted pound (#) weight in a paper’s name does not mean it is a thicker sheet, but weighs differently when the base sheet size is weighed.
So, after all these years, I knew my uncle was crazy. A name is truly important, but also just as important is understanding what goes into that name. Knowing this will keep you a little more sane when ordering paper.