Dear David, I note that one of the references you quote uses the abbreviation gsm to mean grams per square metre.
When I investigated this some years ago, I found that paper makers also use some other abbreviations. At my paper suppliers I found the following different, and incorrect, ways to describe paper: 100gsm, 90GSM, GSM: 110 Grain:, 150GSM, 80GSM, 80GSM, 80 gsm, GSM: 140, GSM: 140 Grains:, 90 GSM, GSM: 200, 200 G.S.M, GSM: 80, 110 GSM, 100 Gm2, GSM: 150 Grain:, 80 gsm, 110 GSM, Brandname 80, Brandname 80, 80 gsm, GSM: 80 Grains:, GSM: 150 Grains:, Gsm 90, 80GSM, GSM: 80, 80 gsm, 80 gsm, 80gsm, 80 g/m2, GSM: 80, 80gsm, 80GSM, 80 GSM, 80 GSM, 80gsm, 80 GSM, 100 GSM, 80gsm, 80 grs/m, 80GSM, 70gsm, 80 g.s.m, 70g.s.m., 80 G.S.M, 90GSM, 90 gr/m2, 90 gr/m2, GSM (without a number), 80gsm, 80GSM, and GM2. By the way, the correct unit, 'grams per square metre', measures mass divided by area, and its internationally accepted symbol is g/m2 (that's a superscript 2). Paper makers also seem to encourage the use of the jargon terms 'paper weight' or 'grammage', which has the effect of making it difficult for people to know that paper is described in terms of the mass of the paper divided by its area. The correct unit g/m2 not only makes it clear what is being measured but within the unit it also suggests how the measurement should be done � measure the mass of the paper in grams; measure the area of the paper in square metres; divide the mass by the area. Cheers, Pat Naughtin LCAMS Geelong, Australia Pat Naughtin is the editor of the free online newsletter, 'Metrication matters'. You can subscribe by sending an email containing the words subscribe Metrication matters to [EMAIL PROTECTED] -- on 2003-08-30 02.55, David Shatto at [EMAIL PROTECTED] wrote: > There seemed to be some confusion in this discussion, so I decided to do > some research on this, and here's what I found. > > The official term for paper weight is "basis weight." Here's a short > explanation from > http://www.jhoe.com/support-downloads/paper-weight-chart.asp > > "Basis Weight: Basis weight is the standard measurement of an amount of > paper. For example, the basis weight of Bond is determined by the weight > of 500 sheets of 17"x22" paper (the parent size). If a ream of 17"x22" > paper weighs 20 pounds, this is called 20 lb. paper." > > ... and here's their "paper weight conversion chart" in a > well-organized, printable format: > http://www.jhoe.com/images/downloads/pdf/paper_chart.PDF > > To make better sense of it all, here's an article called, appropriately > enough, "Making Sense of Basis Weights." > http://www.tappi.org/index.asp?pid=26849&bhcd2=1062174248 > > It includes the following interesting paragraph: > "The rest of the world, including England, which originally blessed us > with this system, has gone metric and uses grams per square meter as the > standard basis weight of all types paper and paperboard. Changing to gsm > would be a step in the right direction but old customs die hard." > > I found a few weight conversion tables (lb / gsm), and this site has a > very informative page on "How to buy paper - Metric measurements" > http://www.papercatalog.com/HowtoBuy/chapter16.htm > > The following paragraph from this site might be helpful for those who > like calculating things: > "Basic formula: To convert from basis weight in pound to grams per > square meter, multiply the basis weight by 1406.13 and divide by the > square inches in the base sheet. For example, to convert from 20 lb. 17" > x 22"/500, multiply 20 lbs. by the constant 1406.13 and divide by 374 = > 75 g/m2." > > David Shatto > Los Angeles
