Fiber
Paper
is made up of fibers that come from various materials. Different types of fiber material
produce different kinds of grain structures. Wood and cotton are the most
common types of fiber used in commercial inkjet papers. Wood when broken down
generally produces shorter fibers, while cotton forms longer fibers.
Some
paper companies market specialty papers made with other forms of fibrous
materials. The Hahnemühle
Paper Company makes alternative fiber inkjet printer papers such as rice,
bamboo, and sugar cane papers.
Grain
The
term “grain’ in reference to paper refers to the direction fibers are oriented
that make up a sheet, or “grain direction”. When paper is manufactured, the
fibers become oriented in parallel to form the paper grain. Paper sheets are
referred to as being either long grain or short grain. This should not to be
confused with papers having long or short fibers. Fiber makeup and grain
structure are distinctly different. One refers to the direction of the fibers
while the other refers to the size of the fibers.
Grain
direction is always classified in reference to the long dimension of a piece of
paper. In other words, a 9” x 12” piece of paper that is manufactured to be
long grain would have paper fibers that run parallel to the 12” direction,
i.e., long dimension, long grain. A 9” x 12” piece of paper that is short grain
would have paper fibers that run perpendicular to the 12” dimension, i.e., long
dimension, short grain.
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| Books are usually printed on short grain paper. The red arrow indicates the recommended grain direction. |
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| Pamplets are also printed with the folds parallel to the short grain direction. |
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Single sheet forms, like posters and letters, are usually printed
long grain.
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Grain direction can easily tested by tearing the paper along the long dimension
and then on the short dimension. If the paper tears fairly easily and in a
straight line, it was torn “along the grain”. If the tear is ragged and
irregular, it means the paper was torn “against the grain”.
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| The long grain edge in this paper grain test tears relatively straightly,while the short grain edge tears very unevenly. |
The Importance of Knowing Fiber Content
Fiber
content directly influences the image quality and aesthetic preferences for a
printed image. That’s why papers are made with different fiber contents. Stronger,
harder surface papers produce a higher degree of “ink holdout”. Ink holdout
refers to the degree in which ink is able to remain on the surface of a piece
of paper without being unnecessarily absorbed. A high ink holdout produces a cleaner
and sometimes glossier ink jet dot. So, 100% cotton fiber papers, which have a
high ink holdout produce a much sharper image than say, newsprint, which has a
very low ink holdout and produces a fuzzier image.
Hardwood fiber comes primarily from deciduous trees. The fibers
in hardwood are shorter making paper more flexible and smooth.
Softwood fiber comes from almost exclusively conifer trees. The
fibers in softwood are longer making paper more strong and rough.
Cotton fiber is made from 100% cotton fibers. Cotton fibers are
both stronger and more durable than wood pulp-based paper.
Recycled fiber is made from various sources. Recycled fiber can
be very high quality. Non-post consumer recycled fiber from unused repurposed paper
is superior post consumer recycled fiber.
The Importance of knowing Grain Direction
Grain
direction affects the ability of a piece of paper to fold properly. Paper folds
best with the grain, so it is important to have the grain direction parallel to
the fold. Paper that is folded along the grain will have a smooth very neat
fold, whereas paper that is folded against the grain will tend to crack leaving
a rough unappealing edge to the fold. Some digital paper manufacturers will
specify the grain direction for the consumer. The Moab Paper Company denotes
the paper as “GL” for grain long, or “GS” for grain short. Printed materials
that have folds such as books, brochures, greeting cards, etc., are prime
candidates for short grain papers, while posters, post cards, flyers, etc. are
best printed on long grain papers.
Note: Paper coatings and surfaces will be the subject of a
future post.
