I read Cecil’s explanation of why U.S. letter paper is 8.5x11 inches, after which he blew off metric paper sizes as “obsessive” and created by Germans.
There’s one very handy thing about “A”-sized paper. (By the way, there’s “B”-sized papers as well.
All “A”-sized paper has the same proportions. Thus, you can print a hardcover on, say, A3, and put out the paperback on A4 by simply blowing down the text. The layout remains constant.
In the U.S. over the last decade or so, printers are finally starting to use the system the rest of the world relies on. This causes some problems, e.g. books too big for standard shelving, but the benefits far outweigh the hassles.
A link to Cecil’s column is useful when discussing old ones. And, yes, the A series has considerable charms. It looks beautiful and it can be scaled without waste.
I edit a monthly club newsletter. It’s professionally printed up as an A5 booklet, but while I’m working on it at home, I can print it out on A4 sheets for proofreading with no waste or loss of proportions. Definitely a very logical system. But that doesn’t mean the whole A1-is-one-square-meter bit and some other details aren’t just a leeettle bit obsessive.
It’s actually A0 that is one square metre; A1 is 0.5 square metres; etc.
And it’s like everything else in metric, it makes calculations easy. Say I have ream (500 sheets) of A4 paper, weighing 80 gsm (grams per square metre). How much does the ream weigh? Well, 500 sheets of A4 is 500/16 square metres, so the ream weighs 80*500/16 grams, i.e. 2.5 Kg. (And one sheet weights 5 grams.) You can do it in your head. Try doing the equivalent calculation for US paper sizes.
I think it is actually 5 lbs. The 20 lbs is the weight of 500 sheets of the standard 17" x 22" sheets described in the column. The 8-1/2 x 11 is one-quarter of the size of those sheets, so a ream of letter size is one-quarter of the pound weight of the paper.
B sizes for sheets of paper are very rarely used - generally B[number] is the size of a large envelope for A[number] sheets, and C[number] is the size of a small envelope for A[number] sheets. As a C-size is sufficient for all but the thickest stacks of A-size sheets C-size envelopes are much more usual than B-size envelopes.
