In North America the units of measurement are “Imperial”, that is inches, as opposed to metric (mm, cm & meters) as they have in Europe for example. Our basic size for letterhead, copy paper etc. is 8.5” X 11” while in Europe it’s “A4”, which is 210 x 297 mm (translates into 8.3 x 11.7 in., slightly narrower and longer). A similar situation applies to business cards. North American business cards are 2” X 3.5” while the metric size translates into 3.346” × 2.165”. So if you see references to “A” size paper (A0, A1, A2, A3, A4, etc.), remember they are referring to metric sizes.
The convergence of technologies due to digital imaging recently has confused this as we get a number of requests using metric measurements. At some point these will need to be converted to imperial, usually by the printer.
As with all things, most papers come in a variety of grades. Desirable features include whiteness, finish, weight and caliper.
Paper whiteness is measured in North America by the Tappi Scale that ranges from 92 – 100 with 100 being the brightest. Whiteness is more of a factor with less ink coverage documents than full reverse printed ones simply because there is less paper visible. Obvious, but worth noting.
Paper Finishes include coated gloss and matte, smooth, wove, vellum, laid, linen. Their names are pretty much self-explanatory. There are a number of others that I would personally refer to as specialty finishes. Their popularity and hence availability have seriously declined for a number of reasons, I imagine. Not the least of which are cost, industry consolidation and incompatibility with laser technology. These days imitation finishes can be easily printed on plain sheets, saving money while yielding a more ‘custom’ look.
The weight of paper has traditionally been measured by “M weight” (M being the short form of 1000) or “basis weight”. Basically the physical weight of a parent sized sheet. So 20 lb. Bond is described so because 1000 sheets of 11 x 17 sheets (it’s parent size) weigh 20 lbs. Writing papers are grouped with Bonds.
Offset papers including coated are effectively the same as bonds but their parent sizes are different (19” x 25”) so the same ‘real weight’ offset as 20 lb. bond is referred to as 50 lb. offset. Offsets come in 10 lb increments, from 50 lb. to 120 lb. while bonds are generally only produced in 20 and 24 lb.
Text and Cover weight papers usually come as a team. By that I mean there is a heavy weight (cover weight) and a lighter weight (text weight) that are otherwise the same. These are useful for publications where the cover matches the inside. The text weights are usually equivalent to offsets although they don’t necessarily all come in all the weights. The cover weights have a different basis again and also come in 80 lb., 100 lb. 120 lb. but are obviously much heavier. 80 lb. cover does not equal an 80 lb. text or offset.
In addition there are Bristols, which include Vellum, Index and Tag Finishes and weights. They are different again, but I think it’s best to think of them in terms of caliper, rather than weight.
Paper Caliper (Thickness)
Paper caliper and paper weight are very closely related but not necessarily directly related. An increase in physical weight affects caliper but the amount of this affect can vary depending on density. An example of this is what used to be called Postal Hi-Bulk, now sometimes Domtar Reply Card. It meets minimum postal regulations for thickness (caliper) but is less dense, therefore containing less fibers so it’s a bit less expensive than standard papers of the same caliper. The cost factor will be an issue on longer runs. There is also an implication with laser printing in that the heat required to fuse toner is less with a less dense sheet and therefore allows for a slightly thicker sheet to be imaged. This brings a rise in popularity to a totally different method of measurement. Grams per square meter (I know, it’s metric but we need to be flexible these days) is more important these days in the laser world as it describes the paper compatibility with any heat reliant imaging system.
The trend recently has been for thicker caliper business cards. For a long time 10 pt. was a standard. Now 14 pt. and even 16 pt. are popular.
Coated papers are popular in either a gloss or matte finish. The ‘coating’ refers to clay that is on the outside of the paper sheet that creates a much more vibrant substrate for inks. In fact, the official ink colour cataloguing system (Pantone Matching System or PMS) has different colours for the same number on coated and uncoated paper. See my Blog on colour. The difference is much less with laser based toner and in my opinion, you’re better off with a quality laser sheet than coated with most jobs being produced digitally on a laser printer.
Although a bit confusing, understanding these factors, at least in a general way, might help you make a better decision on your next project.
I encourage you to let me know what you think about this, or any entry, or if you have any questions.
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