(Recommendations for customers from: Christopher John/The Printworks Inc. @ http://www.cjpw.com)
What is a score? A score is simply a crease in a sheet of paper that establishes position for a fold. Scoring is a process that sometimes comes as an after-thought when it should be a fore-thought
In many cases, ignoring the importance of scoring can put your project in the less-than-perfect category. Scoring is dependent on stock, caliper (thickness), finish, grain and the printed image itself.
Scoring and paper grain
Paper grain is undoubtedly the most critical consideration when scoring. Almost all paper has grain. Normally, paper grain runs with the long dimension of the parent-size sheet. For example, a 23 x 35 sheet will have grain running the 35" dimension, and is referred to as grain long. If you cut that sheet in half to 17 ˝ x 23, the grain would be running the 17 ˝" way, thus giving you a sheet with grain short. Perhaps you can surmise from this that the best scoring results are achieved when the score and fold is with the grain, allowing the paper fibers to stretch, or separate, without breaking.
Checking Paper Grain
You can check for grain on a piece of stock by folding it in both directions - the smoothest and easiest to fold will be along the grain. For lighter sheets, hold the sheet upright, grasp it in the middle, and tear straight down. Do this both ways and the grain will be obvious by the less ragged tear.
Grain direction—the printer's responsibility
Most print buyers give little consideration to grain direction, since more often than not, jobs are printed on sheets several times larger than the finished product. Besides, choosing the way a job is "laid out" and paper grain is the printer's responsibility; any estimator worth his salt will normally plan a job to run so that scoring and folding will be with the grain of the sheet. But this is not always possible because of available sheet sizes, grain and press cylinder orientation, the final trim size of the job, and in certain situations, cost.
Because of the size of certain jobs, scoring with the grain can be impractical because the waste factor (unusable paper) would be much too high. This is especially true when the paper selected is premium grade and costly. In rare instances, with grain running the same direction as the fold, a job may be folded without scoring, but this is highly unlikely. When the fold is against the grain, scoring is a must and the method and type must be carefully reviewed.
When to score
Scoring is necessary with paper basis weights equivalent to 100 lb text and heavier. Any cover stock must be scored to permit "clean" and accurate folding. This includes the common cover basis weights of 65 lb, 80 lb, 100 lb, 120 lb, 130 lb and higher. Scoring is sometimes done on lighter weight text papers when the end user will do the final folding. The score acts as a guide so the finished sheet can be folded correctly.
A bad score can ruin a good job
The importance of scoring is elevated to perhaps its highest degree when there are heavily inked areas on the sheet. Printed solids and screens and big bold type that crosses over folds bring on the feared "C" word - cracking. Cracking alone can completely ruin the aesthetics of a beautifully printed piece and should therefore be given adequate forethought before printing - most particularly when printing on a coated stock and scoring against the grain. In practice, you should avoid printing, scoring and folding a job with heavy coverage across the fold when the score will be against the grain. It simply makes more sense to plan it properly, spend a few more dollars, and avoid the heartache and disappointments later.
Which side is the hinge side?
The most economical score is done on the printing press. Both the set-up or "make-ready" time and running time can be accomplished at speeds similar to printing, thus the economy. However, and this is a big however, the quality of a press score is not the same as the die score or binder's score. This is not to say that a press score is inferior, it is not. It is dependent on all the issues discussed above: paper weight, grain, ink coverage, and so on. When all the variables are favorable (especially grain direction), a press score is more than adequate.
Conversely to what you may think, a correctly scored and folded sheet will have the "ridge" or bump created by the scoring element on the inside to minimize the stretch of the paper fibers. This process actually creates a "hinge" that allows the sheet to bend without cracking. Normally, the thicker the paper, the wider the score.
he die score is an absolute must when your project is printed on heavy cover stock, and/or with a coated finish and heavy ink coverage. In this instance, grain should not dictate whether to die score or press score - opt for the die score for maximum quality
Die or Channel Scoring
A die or binder's score is a superior method for creasing paper stocks. It can be done using a steel rule with a rounded edge embedded in a wood base, either by itself or as a part of a die-cutting die; or it can be done on a letterpress (see "Engraving")
Because of higher material cost, longer set-up time, and slower running times, die scoring is more expensive. However, when your job requires die cutting, such as a presentation or pocket folder, the die score is normally inserted into the cutting die and does not increase the cost.
The die score is an absolute must when your project is printed on heavy cover stock, and/or with a coated finish and heavy ink coverage. In this instance, grain should not dictate whether to die score or press score - opt for the die score for maximum quality.
Department of Communication, Seton Hall University