Understanding grain direction
How the size a sheet of
paper is reported gives important information to the ‘grain direction’ of
paper. When a sheet is reported to be 760x560mm size, like Bockingford, this
shows the sheet is ‘Short grain’.
How the dimensions are
written denotes where the sheet ‘sat’ on the paper machine when it was made.
The first dimension eg 760mm, is always the width, and the second dimension eg
560mm is always the length. Bockingford is 760x560mm, which means it was made
in a landscape shape (as opposed to portrait). Because the second dimension
shows the length of the sheet is shorter than the first (width) dimension the
paper is called ‘Short Grain’. If the dimensions were the other way around it
would be called ‘Long Grain’.
Grain direction is
important, as there’s an inherent weakness with paper in the papers length.
This is especially important if the paper is due to be folded. However, the
Mould Made papers, grain direction is a lot less pronounced than with standard
Fourdrinier (machine made) papers, as the fibres tend to lie in a more random
pattern.
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