August 2006:
Got Grain? Use it Wisely!

In spite of the clay fillers, coatings and other additives it contains these days, paper is still an organic product. As such, its behavior can be unpredictable. During binding and finishing production, paper is subjected to moisture, heat and force - all of which can cause paper to expand or contract, to become brittle or even to fall apart.

The grain direction of your paper is critical to the strength and appearance of your finished product, and it’s handled differently based on the type of project. Here are a few important paper grain tips to keep in mind when planning for each of the following processes:

Binding a book cross-grain (left) may result in waviness and poor quality as paper expands, while a grain-parallel layout (right) allows paper to expand with the spine.

Adhesive Binding
Ideally, grain direction of an adhesive-bound book will be parallel to the binding edge. However, the trim size of the book often dictates how paper will be aligned on press, which may or not be optimal for binding.

While binding a book cross-grain may not pose problems, there are two factors to keep in mind: 1) Paper cannot expand beyond the glued edge of the book, and 2) paper expands perpendicular to the grain direction. If a book is bound cross-grain, paper expansion may cause wrinkling at the spine, uneven appearance along the face of the book and reduced spine strength (see image at right).

Folding Cartons/Packaging
The rule of thumb for most folding applications is to fold with the grain whenever possible. When using thicker stocks such as corrugated board, however, the opposite is true. Scoring and folding is often cleaner and more accurate when performed cross-grain on packaging-weight stocks.

Mounting
The mounting of a litho sheet to a backing substrate can be performed either grain-parallel or cross-grain. The decision should be made based on the size, thickness, finish and other details of both sheet and backer. For some mounting applications, mounting the sheet against the grain of the backer will help minimize curling. Let The Riverside Group help you determine the appropriate layout for your mounting project.

The Riverside Advantage
At The Riverside Group, we differentiate ourselves by providing sound advice in every area of post-press planning and execution. Our complete range of binding and finishing solutions includes hardcover and softcover adhesive binding (including PUR), mechanical binding, folding, gluing, collating, die cutting, foil stamping, UV coating and much more. Give us a call today to discuss your next project.