machine direction (MD)
Erklärung:
Indeed Schmal-/Breitbahn = long/short grain. However, these terms refer rather to the paper itself (how it was cut in relation to the direction of the original paper roll). In relation to the printing process, the terms 'machine/cross direction' are more relevant.
"Machine and Cross Direction
Paper has a definite grain direction due to greater orientation of fibres in the direction of travel of the paper machine. This grain direction is known as machine direction. The cross direction is the direction of paper at right angles to the machine direction. Some of the properties vary with the MD and CD and hence the values are reported in both the directions. While sheeting the paper, machine and cross direction are to be kept in mind and the sheet cutting to be done to suit the end use requirements. Examples: 1. All printing papers are to be cut in long grain (The biggest dimension in the grain direction). 2. Book papers fold better and the book stays open better if the sheets are out so that the machine direction runs up and down the pages. 3. Wrap around labels for metal cans and bottles are to be cut with the machine direction vertical to obtain greater flexibility about the can. Long grain and Short grain : The sheet is in long grain if the larger dimension is parallel to grain (MD) direction. The sheet is said to be in short grain if the larger dimension is parallel to cross direction (CD)." (first link below)
The choice of direction is important in sheetfed offset printing due to the fact that paper behaviour is different along/across the grain, mainly in view of: 1) elongation, 2) curling, and 3) folding. Here's some more to it:
"Paper Grain - All paper has grain. Long grain paper has the grain running the length while short grain paper has the grain running the width. Why is this important? If you need to fold the paper, you MUST fold it with the grain otherwise you will get a ragged fold. You can buy most paper with either long or short grain." (second link below)
"Die zugehörige Abkürzung lautet "SB". Mit dieser Bezeichnung wird eine Aussage über die Faserrichtung (besser Laufrichtung) eines Blattes oder Bogens gemacht. Bei Schmalbahn liegt die längere Seite parallel zur Laufrichtung. Beispiel: 70 x 100 cm bedeutet Schmalbahn, Gegenteil: 70 x 100 cm bedeutet Breitbahn. Das unterstrichene Maß zeigt die Dehnrichtung."
http://www.buchbinder-chemnitz.de/start.htm?url=glossar/schm...
"Laufrichtung
Die Laufrichtung ist die Richtung in der das Papier bei der Herstellung durch die Papiermaschine läuft. Die Laufrichtung beim Papier/Karton zu kennen ist wichtig, da Papier sich durch Feuchtigkeit ausdehnt und zwar immer quer zur Laufrichtung. Dieses Verhalten kann beim Drucken zu Schwierigkeiten mit der Passgenauigkeit der einzelnen Druckgänge führen. Desweiteren lässt sich Papier besser in Laufrichtung verarbeiten. Die Laufrichtung wird auch als Maschinenrichtung bezeichnet. Papierbogen werden je nach Laufrichtung als Schmalbahn (Laufrichtung parallel zur langen Seite) oder Breitbahn (Laufrichtung parallel zur kurzen Seite) genannt. Bei der Papierbogen-Bestellung wird die Laufrichtung entweder durch ein M (Maschinenrichtung) oder durch eine Unterstreichung der Dehnrichtung kenntlich gemacht, z. B. 35 cm x 50 cm M oder 35 cm x 50 cm.
Biegeprobe
Zwei Papierstreifen mit verschiedener Laufrichtung biegen sich unterschiedlich stark.
Feuchtigkeitsprobe
Ein angefeuchtetes Blatt Papier wölbt sich in die Maschinenrichtung
Nagelprobe
Ein Blatt Papier, an dessen Kanten man mit den Fingernägeln entlangfährt, kräuselt sich an der Dehnrichtungsseite
Reißprobe
Beim Einreißen eines Blattes Papier, entsteht in der Dehnrichtung ein gezackter Riss."
http://www.geldsetzer.de/Glossar/g_l.html
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Note added at 2 days 10 hrs 56 mins (2003-12-23 05:50:16 GMT)
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William:
Just to make sure, I consulted a friend of mine, a printing shop manager, who\'s been in the business for 30 years.
In fact, Schmal-/Breitbahn = long/short grain, *which is equivalent to* machine/cross direction (MD/CD).
Faserrichtung = grain direction; Laufrichtung = machine direction.
That is, Laufrichtung refers to the direction of the paper roll during the manufacturing of the paper, *not* to the direction of the sheet movement through the printing press (press direction, sheet feed direction).
My confusion stemmed from the fact that in my language we use a phrase roughy equivalent to \'machine direction\' to signify sheet feed direction through the printing press.
Anyway, in English \'machine direction\' (MD) is indeed an equivalent of \'long grain\' (Schmalbahn). While doing some additional research, I found out that \'machine direction\' and \'long grain\' were used at about the same frequency, in relation to commercial printing (as far as Google can be trusted).
In view of all this, Rebecca\'s sentence would be about the difference in a printing sheet\'s properties (namely elongation) when printing grain long, as opposed to printing in cross direction. (Or in long grain, as opposed to short grain, or in MD, as opposed to CD.)
To close with, I found this excerpt that says it all (I think):
\"All machine-made papers have the property of grain - the direction in which most of the fibers lie. Grain is determined by the manner in which fibers align as the sheets are being manufactured in the paper machine.
As the slurry flows from the headbox to the moving fourdrinier wire of the machine, the fibers have a tendency to align parallel to the direction of the flow just like little logs floating downstream. Despite efforts to minimize this effect, most fibers continue to align themselves in the same direction. The direction the majority of fibers are pointing in any given sheet of paper is that sheet\'s grain direction.
The terms grain direction and machine direction are used interchangeably by paper manufacturers. The graphic arts industry uses such terms as folded parallel to the grain, printed grain long, and grain optional to specify how a printed job should be produced Paper grain is very important to commercial printers, and can impact a job in a number of ways, as detailed below . . .
Folding: ....
Dimensional Stability: ....
Rigidity: ....
Tearing: ....\"
http://www.anro.com/mailing-news/ink7.html
Quelle: http://www.biltpaper.com/p_properties.asp
Quelle: http://www.invitationsetc.com/m2_pt.htm
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