The grain of paper

After years of bookbinding, often I am still confused by the grain of paper. Today I was at war with my paper again while making business cards. I have this beautiful flyleaf paper, white with a linen finishing, very cool paper, but much to thin for business cards. So I decided to glue this paper on both sides of a sheet of 250 grams A4. To prevent this new formed thick sheet from warping, the grains had to match ... so thinking, folding, doubting and to be sure ... reading ... So this is a refreshment for me ... maybe it is convenient for you as well ...

The grain of the paper is important for

• The final fold of your booklet. You want the page to curl from side to side, so you can easily turn the pages and the book opens flat.
• Prevention of warping. You don't want your booklet to end up with warped covers.
• Creating crisp, even folds and prevent cracking.

It is always easy to work with handmade paper. The pulp is allowed to settle randomly, so the fibers are multi-directional. Unfortunately you often don't have the luxury to work with this kind of paper, so you have to determine the grain of the mass-produced paper. In the mechanical process, the water flows across the surface in one direction, so the fibers get their grain.

Ideally the grain of the paper and the boards of the side-covers always run parallel with the spine of the book. Keith Smith has a very simple example to clarify the direction of grain; a sushi mat. The direction of the wooden sticks represents the direction of the grain in paper or book board. Just as the mat rolls easily in one direction, so does paper. As a true sushi lover I certainly will remember this one :)

Unfortunately you need some more info to determine the grain direction. Grain runs parallel with the direction of the paper in which there is less resistance to folding. If you can't determine the resistance by folding you can dampen a little piece of paper. It will curl immediately, the axis of the curl is parallel with the grain. The curl shows the direction the paper should be folded.

To prevent warping it is important that the grain of the flyleaf and the book board are identical. Book board is easy to test. Just bend a full sheet, the board will flex more easily in the direction that is parallel with the grain. Since it is very difficult to determine the grain for small parts of cardboard, make sure you put lines on the big sheet, so you can always see the grain at the small parts later on.

Besides paper and cardboard, book cloth also has a grain. This grain is typically parallel to the selvage or outer edge of the cloth. This is often very confusing, because when you buy book cloth it is typically rolled cross-grain. So be careful with that one!

One basic rule you can always remember is that the grain usually runs parallel to the long side of the sheet ... although not always ... so remain wary :) 

More tricks & tips are always welcome, so please don't hesitate to make a comment!