GRAIN DIRECTION

HOW TO DETERMINE GRAIN DIRECTION

1. Tear a sheet in two directions. It will tear easier and straighter parallel to the grain.
2. Fold a sheet in two directions. It will fold smoother with the grain.
3. Generally speaking, paper with a laid finish has the grain parallel to the chain marks. (See Patterns in Paper pages.)
4. With a small piece cut from a sheet, wet one side. As it dries it will curl parallel to the grain. Be sure to mark the sample’s original position from the folio sheet.
5. Moisten two right-angle edges of the sheet, and press between two fingers. As the sheet dries, the edge across the grain will be wavy; with the grain it will be straight.

IMPLICATIONS

Grain direction can dramatically affect printing results, so it is imperative that the direction be appropriate to the paper, the press and the particular job.

For proper feeding on small offset presses and duplicating equipment, grain direction should be parallel to the direction of sheet travel to minimize its rolling up or curling in the delivery. Grain direction of heavier-weight papers may have to be put parallel to the press cylinder axis to provide better conformance to the curvature of the cylinders.

Grain direction affects stiffness and is important for specific end use requirements such as display cards, posters, index cards, file folders etc. For these items grain direction should be perpendicular to the supporting edge to minimize sagging.

Letterheads should have long grain for greater stiffness. Sheets processed on high-speed copier equipment should have grain perpendicular to their advancing edge.

On presses larger than duplicator size, where registration is often critical, paper should always be run with the grain direction parallel to the cylinders. This allows the press operator the option of changing the cylinder packing to adjust for minor registration problems caused by paper acclimatizing to the pressroom environment.