How Paper May Impact Printing
Clearly paper can exhibit a wide range of characteristics, and the trait of each paper will factor into deciding which paper is best for your job. For example, when a professional printer discusses a paper’s basis weight, he’s referring to the weight of 500 sheets of standard size paper. There are different classifications of basis weight, such as bond, cover, index, tag, and vellum bristol. Important factors to consider when selecting the best basis weight for your project include the following:
Opacity: heavy sheets provide more opacity. If transparency is an issue, increase your opacity by securing a heavier weight.
Bulk: heavier sheets of the same grade are thicker
Stiffness: the heavier a sheet the stiffer it is. If a client is printing a thin brochure, using a heavier sheet may help add volume and make it feel more substantial and authoritative.
Cost: Weight is expensive. With each increase of basis weight, the cost of your paper will also increase anywhere from 15 – 20 percent. On the converse, dropping basis weight will decrease the cost of your project.
Mailing Weight: Heavy paper is difficult to mail, especially if high volumes exceed certain limits, so pay attention postage regulations.
Folding: Heavy sheets are more difficult to fold, requiring additional labor.
Caliper refers to thickness of paper, also known as bulk, which is measured in thousandths of an inch. Caliper is also occasionally referenced as Point, where each point represents one thousandth of an inch. Points may be the must useful language to refer to caliper as it makes the most logical sense. For example, a sheet that is a 10 point stock has a thickness that is 10 one thousandths of an inch. Likewise, a 12 point SBS Board would have a thickness of 12 one thousandths, and so on.
When it comes to printing, typically caliper need not factor into the equation. However, there are two specific cases where caliper certainly matters: Postcards and Pages per Inch.
Postcards are required to be no lower than 7 point and no higher than 11 point, if they are to fall within usual postage rates. If a card dips below the minimum or exceeds the maximum the post office will either charge you a much higher rate of postage or, even worse, refuse to mail your card, so this is one instance where it pays to be aware of your paper’s caliper.
Pages per Inch is term that has everything to do with caliper and, if ignored, can lead to some significant problems toward the end of the publication process. Pages per Inch is the number of pages a grade requires to reach one inch. Each sheet of paper constitutes two pages (front and back) so you must double the number of sheets it takes to reach one inch when stacked horizontally. This number matters when it comes to binding pages, as sometimes if the pages are too thick, they won’t actually fit into the intended binding, cover, or even a three-ring binder. Because most long projects will eventually be bound, it’s of critical importance to make sure the final print out will fit into the proper bindings. Longer publications may be better served by lighter paper.
Brightness represents a paper’s level of reflectance of a specific wavelength of blue light. Typically, a sheet’s degree of brilliance is determined by the GE reflectance meter, a scale that runs 1 to 100, 100 being the most brilliant and most desirable.
Brightness is a key component in evaluating paper grade. For both coated and uncoated papers, glossy and regular, as the brightness level of a sheet increases, so does the overall value and grade. Brighter papers tend to have a higher degree of opacity, while the dimmer sheets tend have a slight transparency. Brighter paper offers better readability, with a strong contrast between ink and paper, allowing for brilliant clarity visual potential. For all these reasons, sheets with higher levels of brightness are the most expensive.
The whiteness of a sheet is similar to its brightness, but whiteness ultimately provides a more complete account of paper quality, identifying subtle degrees of difference. For example, the human eye can look at two sheets of “white” paper, each with the same level of brightness, and yet notice that these two sheets of paper may look slightly different. One might have a slight shade of blue, while the other a subtle pink. Indeed, there are many kinds of white and the whiteness meter helps specify your choice.
Smoothness refers to the surface of an uncoated sheet of paper and is calculated by using the Sheffield Smoothness test. Once appraised, a very low number will denote an extremely smooth plain, while higher scores indicate a rough, textured finish.
Smoother surfaces allow for better printing and better reproduction. However, rough finishes, known as Vellum or Antique, tend to absorb ink faster, in addition to also drying faster and allowing for added dot gain. The real advantage with a vellum finish comes in financial incentive, as the it will always be les expensive than a smooth finish, however, you can get paper with the same brightness and basis weight for far less money if it’s with a vellum finish. In addition to saving money, this is a subtle way to add thickness for clients that seek a more substantial look, but don’t want to pay for a heavier paper. This benefit aside, smooth finishes seem to be more popular and more likely to appear in stores.
If you look closely enough, you’ll see that every paper has a grain direction. Because paper is derived from trees, paper consists primarily of long fibers. At the paper mill these fibers go through a correction process to make sure all grains are running in the same vertical direction, and this is what later forms the grain direction of each sheet of paper.
Grain direction can have a big impact on thicker papers that may be folded for a brochure or pamphlet, as it’s exceedingly difficult to fold against the grain without also causing breakage. Also, be sure that any images you might print with a laser printer are arranged portrait style, or long-ways, so they will hold consisted with the grain. Printing images across the grain direction will distort the quality and clarity of the image.
Opacity refers to the transparency of a sheet of paper, or the degree in which one can see through to the other side. Opacity is scored on a scale running 1-100, 100 signifying the highest level of opacity, meaning the opposing side of the sheet is not seen at all. Obviously, opacity can have a major impact on projects that require double-sided printing.
Sheets without a finish actually tend to have great opacity than their coated counterparts, and higher grades suggest higher levels of opacity. Opacity is achieved through presents of wood pulp and bulk, so the heavier weight papers and papers with added caliper have great opacity. Obviously projects that will require copious text on each side will call for more opacity than projects where only one side is used, or there is an unequal balance of text. Novels, for example, require paper with great opacity.
Key physical characteristics divide both coated and uncoated sheets into separate, ranked grade classifications. These classifications help supply buyers with a better understanding of the different qualities and options available for them to select from.
Coated Papers are appraised by their brightness and smoothness. Similar grades should be equivalent brilliance and accept ink easily for printing and reproduction. Opacity does not factor into the equation.
Uncoated Papers are ranked by their degree of brightness and opacity together. In this case, smoothness does not factor into the equation.
Grades within equal classifications should be available for an equivalent price.
Because grades are appraised and regulated by the same consistent standards, it doesn’t matter which mill you buy from in terms of quality, provided you’re buying the comparable grade. A grade from one mill will be comparable to the same grade from another. This way you can find the exact grade of paper you need no matter where you’re ordering from or where you are.