Grain Direction

Determining Grain Direction

What is Grain Direction? Paper is made up of individual fibers (cotton, wood), which are held together, often by fillers, but sometimes just mechanically by being dried together as a group. In general, hand-made paper does not have a distinctive grain direction because the pulp slurry is poured into a mould and lifted straight up and out of the water. Whereas in a commercial paper facility, the web of pulp is traveling through the papermaking machine  in a fast, forward moving direction. This forward movement tends to make all of the fibers line up parallel to the direction the web is traveling, thereby creating what is called grain direction.

Imagine on a microscopic level that the paper is a  bamboo mat, like the kind the Sushi makers use to roll up the Sushi. All of the bamboo sticks are going in the same direction held together by the flexible strings of the mat. Image how easy it is to bend the mat parallel to the bamboo sticks. Then image trying to bend the mat against all of those sticks. It would give you tremendous resistance and if you succeeded you would likely have cracked the sticks.

The same is true of commercially made paper and boards, bending and folding parallel to the grain is easier and produces a fold that is less likely to crack, while folding against the grain will likely cause distress to the fibers resulting in a rough, cracked looking fold. This concept is used in Technique #1 for Determining Grain Direction.

Paper also swells when it gets wet. Image those same giant fibers. If you get them wet they will get wider, like eating too much food, we swell in the middle, but we don’t get taller. Using this information you will use Technique #2 for Determining Grain Direction. Kids and big kids love this test because you get to lick the paper. If you don’t want to lick it you can apply moisture with a slightly damp sponge and besides, some paper coatings taste terrible. Have Fun!

Why Should You Care? Once again, folding and scoring with the grain of the paper makes a much cleaner fold and makes a book that flows, because the paper is rolling, as you turn the pages, with the grain. Again, image that your pages are those bamboo mats. See how easy the pages will turn if the bamboo sticks are running parallel to the spine. I’m sure you have all read a paperback book and struggled with is closing on you, sometimes to the point where you had to crack the spine to get it to open so you could read the words close to the gutter (binding area). These books are made with the paper grain, not running Head to Tail, but running from the Spine to the Foredge (the edge of the book you open). Here ends my exhaustive dissertation on Grain Direction and why it is important to the proper and enjoyable functioning of your book. You don’t want your clients struggling with your book you want them looking at your work.

Technique #1 for Determining Grain Direction

You can get the hang of this exercise first by using an ordinary piece of copy paper, you don’t even have to cut it square, because the grain on this type of commercially produced paper is so strong and unmistakable. This feel method works best when trying to determine the grain of a board, such as mat board or bookbinders board. With board you just gently bend them. They will bend more easily in one direction than the other.

1.  Cut a  square piece out of your larger paper, making one edge wavy so you can marry it back to the larger sheet. A rectangular piece can fool you, by the weight of the long dimension giving the illusion that it is easier to bend. Therefore,  make the cut away piece as  square as possible.

2. Take the square piece of paper and gently bend one edge toward the other, creating a tunnel, do not crease. Lay the palm of your hand on top of the tunnel, gently bouncing it up and down, and feeling how much resistance the paper is giving you.

3. Repeat in the other direction. You will feel that one direction gives you much less resistance. This less resistance indicates that the tunnel is rolling with the grain. You are bending parallel to the fibers, not against them.

4. Take you finger and point it into the tunnel with the least resistance, Your finger is pointing in the direction of the grain. Draw an arrow in the direction your finger is pointing.

5. Now marry this cut off piece back to the larger piece of paper, by lining up the wavy edge. Transfer the arrow to the larger sheet. In the papermaking world lingo, if the arrow is parallel to the short dimension of the paper it is called “Grain Short”. If the arrow is parallel to the long dimension it is called “Grain Long”.

Technique #2 for Determining Grain Direction

This second technique is usually so definitive it can be used to check papers that have a weak grain direction that is hard to determine using Technique #1. I use #2 to double check Technique #1. It also uses much smaller sections of paper, so if you want to preserve as much paper as possible Technique #2 is the one to start with.

1.  Cut 2 thin strips, out of your larger sheet of paper, one strip along the width of the sheet and the other along the height. They should be long and thin approximately 1/2″ x 2″, having been cut out in opposite directions. IMPORTANT: make each piece slightly different from the other so you can tell which came from which part of the original larger sheet when you are marrying them back together.

2.  Dampen only one side of the long strip by either licking it or applying moisture with a slightly damp sponge.

3.  You will notice that it will start to curl. This is a result of the fibers swelling from the moisture. It is curling because only one side of the fiber is swelling while the other side is remaining stationary.

4.  As is Technique #1 use your pointer finger to point in the direction of the curl. The paper will be curling around your finger. Draw an arrow in the direction your finger is pointing.

5.  Repeat with the other strip. It should curl in the opposite direction. Draw your arrow.

6.  Marry the strips back into the larger sheet. Both of the arrows should be pointing in the same direction.

7.  Transfer the arrow to the larger sheet. In the papermaking world lingo, if the arrow is parallel to the short dimension of the paper it is called “Grain Short”. If the arrow is parallel to the long dimension it is called “Grain Long”.

Ta Da! You now know how to determine the grain of the paper. For us bookbinders it is very important that the board and paper grain run parallel to the binding edge of the book. This means that the grain direction runs from the Head (top) of the book to the Tail (bottom).

Grain direction also plays a roll when gluing, especially paper to a board. The shrinking of the paper as it dries can pull on the board causing it to warp. Just like it wood working I have to apply something to the opposite side to counter act the pull on the front, otherwise the board is dished. This is why I am a fanatic about grain direction.

DWELLER BY THE STREAM BINDERY

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