The paper fibers decide the course

Further processing If the wrong running direction is selected, the pages will curl, reduce the
impact resistance, it blows up the perfect binding - and the whole
creative performance is a waste of time and paying attention to the direction of travel is immense
important for printing and further processing - especially binding
- and for the subsequent use of the printed product, because
The fibers are damaged by moisture, temperature and stress in the
Printing and finishing machines in the transverse and longitudinal direction
behave differently. While the paper is tensile in the running direction,
is resistant to folding and stretching, it is lacking in the transverse direction.
equivalent tensile strength. It also expands in the transverse direction at
exposure to moisture. And so the wrong
running direction:
- Waviness in the binding or spine of brochures and books.
- By breaking the grooves in the book cover.
- By cracking the adhesive binding when exposed to moisture.
- Due to automatic, unwanted closing of the brochure
(although this could also be due to the adhesive binding).
- Due to register differences.
- Due to curling of labels.
- Due to inaccuracy in the composition (image connection) of
posters, which consist of a large and small sheet (with
varying degrees of delay).
- Poor flatness of laminated covers, folders and so on, or of the binding material of book covers.

How the running direction is created
The running direction of the paper fibers is created during paper production in
of the paper machine, which have a different working or
screen width (transverse direction). For example, the
Büttenpapierfabrik Gmund (Bavaria) via a machine that produces 156 cm wide
of paper can be produced at Ziegler Papier in Grellingen BL is
this measurement is 331 cm and at M-real in Biberist SO, 564 cm wide
paper rolls are produced.
The paper pulp is produced at high speed in the paper machines.
from the liquid to the solid state by dewatering.
The fibers arrange themselves in the flow of the longitudinal sieve in longitudinal
or running direction. This results in the following (machine) running direction
also the greater stiffness and strength of the paper, respectively
Cartons.
The finished paper produced by the paper machine, coating machine (papers with
coated surface) or from the calender (papers with a glossy or coated surface).
matt surface) is produced on a steel roller, the so-called
called a reel spool, wound in the working width. This paper
is still produced at the paper mill in accordance with dealer or
Bulk order of paper rolls in the desired width for
web-fed rotary printing and formats for sheet-fed printing respectively
assembled.

The devil is in the detail
The best way to fold paper is in the running direction. Start with this
often the differences between printer and bookbinder. The
Offset printers usually process paper and cardboard in
Narrow track (SB). The running direction here is parallel to the
pressure cylinder and the register is more accurate. However, as already mentioned
the running direction for books and brochures for quality reasons always
lie parallel to the back. In other words, it can or must
multicolor printing can also be carried out in wide web (BB) if the
further processing - with corresponding reservations in the
Passer (exact se-tenant). Otherwise the only option is to use a
other sheet and/or press format is the alternative.
In web printing, the running direction is determined by the paper web. Since
but in the case of rotary presses a distinction in the
web width of horizontal and vertical sides, the following also applies here
observing the running direction parallel to the collar.
For bottle labels, the running direction should be parallel to the
bottle base, provided that the labeling machine in the
winery is not subject to any other regulations. And in the production of
Folding cartons should have a running direction transverse to the glued seam, parallel
to the bottom of the box or at right angles to the standing direction - depending on the
Automatic packaging machine.
For unbound folded products, the running direction must always be
must be parallel to the last fold (as with books and brochures).

In general, before creation and printing, the client or
The relevant conditions must be clarified and agreed with the customer,
to be protected from unpleasant surprises.

Recognizing the direction of travel
But how can you determine the correct running direction? Here
there are various ways, including the wrong way. There is the nail and
the tear test. These tests still persist in the
relevant specialist literature. Almost a quarter of a century ago, warned
the paper trading company Mühlebach AG, which was still operating under the name of
in Lupfig (now Antalis) that such samples could lead to false results.
conclusions and should therefore no longer be used. These
methods are therefore not (or no longer) recommended from today's perspective.
The running direction of the paper or cardboard can be set using three
possibilities can be reliably and clearly determined: By means of
bending test on the one hand or by the moistening test on the other
(see box). Whether the knowledge gained from the sample is then really
can usually be determined by means of an arrow on the
paper packaging, which marks the direction of travel.

Hans Joachim Laue