Book Binding Secrets: Paper Grain

Book Binding Secrets: Paper Grain

Paper grain – It is a topic I have explored in my first two Journal posts. But today, I'm going to go backwards and explain what paper grain is, for any book binding newcomers. Also, I'll explain how to find the grain direction on papers in our stash and before you purchase papers online.

What is paper grain?
Paper grain is the direction the fibers are laid with the paper is being traditionally manufactured by machine. (This information does not apply to handmade papers.)

Paper Mill Paper Production

The direction the fibers are laid determines the paper grain. Typically paper is made in long strips that are rolled on large drums. Therefore, the paper is long grain, running the length of the roll. How the sheets are cut from the roll of paper determines what grain direction the paper you purchase will be. As we learned in my Paper Math post, you can gain the desired grain based on how you trim the paper, if you purchase larger sheets of paper.

Why is paper grain important?
Paper will fold and glue smoothly when folded along the paper grain. Therefore, when folding the paper to make book binding signatures, you want the fold/spine to go parallel to the grain direction. This is especially important when making a hard cover, glued book structure. Paper expands and contracts with moisture. And you want the book to lay straight along the spine of the book. So the grain of your paper when folded, should run the same direction as the spine of your book.

Folding against the grain may cause cracking and flaking of the paper, especially the thicker the sheet. Some papers are thin enough to "cheat". But, they will not perform as well if they are glued. 

What is long grain paper?
Long grain paper is paper whose grain runs the longest dimension of the paper. An 18" x 24" sheet long grain means the grain direction runs along the 24" length of the paper. An 11" x 17" sheet, long grain means the grain direction runs along the 17" length of the paper. 

What is short grained paper?
Short grained paper is paper whose grain runs the shortest dimension of the paper. An 8.5" x 11" short grain sheet means the grain runs along the 8.5" length of the paper. Therefore, you would fold the paper in half, horizontally to make a 5.5" x 8.5" folded signature. A short grain sheet of 9" x 12" paper means the grain runs along the 9" length of the paper. Therefore, you could fold the paper in half, horizontally to make 6" x 9" folded signatures.

How to find the paper grain before you purchase papers
When searching for paper online, the paper grain may not be listing in the description for the paper. Especially, if you are not purchasing papers traditionally used for book binding or paper not from a shop that caters to book binding. But, don't let that deter you. You can determine the grain of paper in a variety of ways.

If you are sourcing paper directly from the paper mill, you can consult their website and they should offer spec sheets on their. products. There you can usually find out available weights, colors and grain direction. Below is a snap shot of the spec sheet from the 11 x 17 papers I used to carry in my shop. On this spec sheet, the grain direction is in bold. On some manufacture specs, the grain direction is underlined.

Xerox Digital Paper Spec Sheet

What if you aren't buying paper from the mill or a mill store?
Case and point, my drawing papers I used to print in my shop. In order to ascertain the grain direction of those papers, I had to contact the manufacturer of the paper. I contacted School Speciality, since I did not know the mill making this paper. They emailed me back with a drawing of the paper grain, straight from the mill floor.

So, if you have a paper you find online and you can't find the paper specs, call, email or chat with the store to see if they have the information. If not, see if they can give you the name of the mill/company that produces the paper so you can contact them. I have yet to reach out for this information and not receive a response. They want you to make a purchase, so they are happy to answer any questions you have.

How to determine paper grain for papers already in your stash
There are lots of videos and blog posts on the web for ways to determine paper grain. So, I'm gonna keep it short and tell you what I do. I use the "bounce" test. Take a sheet of paper, place it on you desk and bend it over so that the two vertical edges meet, but it's not folded. Bounce the round edge and notice the resistance. Repeat but this time, bend the paper so that the two horizontal edges meet. Notice the resistance. Whatever direction gives you the least resistance is the direction the grain is running. 

To test my results, I fold the paper in half In the direction I think the grain is running. If it is the proper grain direction, it should fold easily and the edge should be crisp. Just to test, fold the paper in the opposite direction. It should not fold as neatly and there may be creasing and cracking; proving it is not the grain direction.

Questions, leave a comment below or send a note through the contact page. I'll help you in any way I can. And sign up for my email list below, so you know when my new Journal entries are posted.

Happy Book Binding!


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