The grain direction of paper is an important factor to consider when planning your print projects. It affects how the paper prints, folds and binds. Simply put, paper folds and tears more easily with the grain than against.

The grain direction is determined by the direction in which the paper fibers are aligned. Paper with fibers that parallel the long dimension of the sheet is called grain long. And paper with fibers paralleling the short dimension of the sheet is called grain short. Keep in mind that the grain runs in both directions in many papers.

Paper manufacturers usually note the grain direction in swatch books by underlining the dimension of the sheet with the grain direction. So, on a 23 x 35 sheet, the grain runs long.

The impact of the grain direction on your piece depends upon the design, choice of paper, and level of difficulty of folding and binding. Consider these facts:

• Paper folds more easily with the grain than against it.

• The binding is stronger when the grain direction is parallel to the binding edge.

• For sheetfed printing, the paper is usually more stable when printed grain long.

• For web printing, the grain always runs in the direction of the web (around the cylinder).

• Because of the moisture in the air and the dampening solutions on press, paper may expand slightly. It's particularly important to run the job grain long when printing a job that requires tight registration.

• When lasering, if the paper grain is not parallel with the rollers of the lasering equipment, the paper will more easily jam, slowing down production.

• Paper can roughen or crack when folding cross-grain, especially with heavier-weight papers.

• Heavy papers may need scoring first if they fold against the grain.

Tip:
To determine the grain direction and get a sense of whether the paper might crack, fold a sheet of paper in half one way and then in half the other way; apply equal pressure to each. The fold that runs with the grain will fold more easily and the crease will be relatively straight. If the folds look the same, the grain probably runs in both directions.