What paper thickness do different GSMs represent in real life? As an online company we are aware that selecting a paper weight without touching and feeling the paper can be a bit daunting. If you’re not in a rush for your print then that will cover the whole range of paper stocks available. If you’re in a bit of a rush then let us translate these seemingly arbitrary numbers into commonly occurring paper you will have bumped into before now:
Most people can tell you that paper (or stock) is made from wood, but many don't know how a tree is transformed into a sheet of paper. The basics are pretty simple and perhaps you have made paper for a science project or craft project before. While all paper starts out as wood, the end result, be it high gloss freesheet or uncoated offset paper, is determined during the manufacturing process of the paper.
ISO 536 defines , which determine the thickness of the paper. The US and North America use an entirely different definition for paper weights based on . Tables of are also provided.
Freesheet paper is free of groundwood pulp and has a bit higher brightness (whiter) than groundwood paper. Freesheet starts at a number 3 grade. Magazines commonly use 50#, 60#, 70# text weight freesheet options on the interior and 80#, 100# text weight or 66# cover weight freesheet stock on cover options. Freesheet paper is more costly than Groundwood.
A grade is a way of ranking paper by certain composition and characteristics. For example, brightness is one of the characteristics used to determine a paper's grade. A number 5 paper grade has the lowest brightness (less white and uniform texture), from 69-73. A number 3 grade paper has a brightness from 81-84.5. Number 1 grade paper has 89-96 brightness. Most magazines run on #3-#5 grade stock.
The table might help you navigate the confusing waters of paper metrics. Following the table are some comments about the thickness and other characteristics of card stock commonly used in the U.S., including the stocks recently used by several Polish and one Ukrainian publisher. All of the models tested were of 1:33 aircraft. My sense is that ship models get the same stock and printing quality.
While most experienced stationers prefer slightly heavier paper stock, the “right” weight depends on the occasion and personal preferences. For instance, 96# business cards do not bend easily and convey an impression of substance. Nevertheless, many business people prefer business cards made of the more common 64# stock because they can get more cards into their wallet or business card case. Working closely with your Guild member stationer can help you determine the paper weight that works best for your circumstances.
The problem arises from something called "basis weight," which probably dates back to the days of hand presses. Papers of different types, or intended for different uses, were traditionally manufactured in different sizes before being cut for commercial use. The basis size for sheets of index stock is 25.5" by 30.5", for cover or card stock it is 20" by 26." The "basis weight" is the weight in pounds of a ream (500 sheets) of paper in the basis size. Even if we compared exactly equivalent index and card stocks (in terms of thickness, grams per square meter, etc.), the index stock would have a much higher basis weight than the card stock, simply because larger sheets of paper are used to figure the weight.
The best way to determine the paper weight that works best for you is to “feel it and bend it.” In general, quality letterhead stationery weighs between 24# to 32#, fold-over notes weigh 64# and card stock weighs between 96# and 120#. Formal invitations for weddings and Bar/Bat Mitzvah can weigh anywhere from 96# to 240# depending on the effect you are seeking to obtain. Also, you frequently see different colored paper stock mounted on top of each other to create a layered effect for wedding and Bar/Bat Mitzvah invitations.
The following table was produced by Lexmark (a U.S. printer manufacturer) to help disentangle the paper weight confusion. It shows the basis weights of six different types of papers, compared to the grams-per-square-meter system. You can see, for example, that the 65-pound Astrobright card stock is actually slightly heavier than the 90-pound Exact index stock (175 g/m2 versus 165 g/m2).
Paper weight is an important consideration in selecting fine stationery. In the United States, paper density is measured in terms of pounds (”#”) for a given quantity of uncut paper and in grams for most other countries of the world. For instance, paper for copy machines is generally 20# (twenty pounds). This measurement term was determined long ago as the weight of 500 sheets of uncut paper at a paper mill. Another mill-term that pops up occasionally is “two- or three-ply paper. “ This refers to sheets of 32-pound paper that are joined together to make heavier paper stock. For instance, 3-ply paper is the equivalent of 96# paper.
Paper weight as specified in the U.S. system can help a little in determining thickness, but it is very far from perfect. Elsewhere in the world, paper is typically measured in a "grams per square meter" system, which tells you exactly how much one sheet of stock, one meter square, weighs. Not perfect, because density and surface can also affect thickness, but it helps. Just to illustrate the problem, Wausau "Exact Index" is listed as a 90 pound index stock, at 165 g/m2. Wausau's Astrobright card stock is listed as a 65 pound card stock at 175 g/m2. Both are about the same thickness.