Dear Mark and All,
The title on your posting, 'Paper weights' has a problem especially when you
contradict yourself in the first line with 'paper mass'.
Neither of these is correct. The physical quantity being measured is
correctly described as 'mass divided by area'. The SI unit for 'mass
divided by area' is 'kilogram per square metre' and a convenient submultiple
is 'gram per square metre', with the symbol g/m2 (with the 2 as a
superscript).
The letters 'gsm' are merely sloppy practice, and they should be considered
with other similar sloppy practices such as those that I have collected here
in Geelong.
What follows is part of my response to an editor from 'Ausinfo', previously
known as the 'Australian Government Publishing Service'. He was supporting
gsm as a unit of measure, essentially by claiming that gsm was an industry
standard.
My reply included:
'I consider that gsm has several potential areas of concern.
Industry standards
This morning I examined the paper stock of Patsey Pacific Publications
(where I work) to verify your claim that �gsm� is the industry standard.
Patsey Pacific currently stocks nine types of paper; they are labelled
80gsm, 80GSM, 100 GSM, 80 g/m2, 80 gsm, 80 g/m2, 90 grs/m, 80 GSM, and
70gsm. From this limited data I could not form a clear consensus of the
accuracy of your claim so I visited a local discount paper store that is
open on Saturday morning.
At the stationers I found the following: 80 g/m2, 100gsm, 90GSM, GSM: 110
Grain:, 150GSM, 80GSM, 80GSM, 80 gsm, GSM: 140, GSM: 140 Grains:, 90 GSM, 80
g/m2, 80g/m2, 80g/m2, GSM: 200, 200 G.S.M, GSM: 80, 110 GSM, 100 Gm2, GSM:
150 Grain:, no data, no data, 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, 80 g/m2, 115 g/m2, 90 g/m2, 80GSM,
80 GSM, 80 GSM, 80gsm, 80 GSM, 100 GSM, 80 g/m2, 80gsm, 80 g/m2, 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, GM2, and 80 g/m2.
Counting the store stock with our own, we had seventy different papers
specified in seventeen different ways. Leaving aside the question of a space
between the numeral and the unit, (preferred in SI) and no space (not
preferred), I counted up the frequency of the various occurrences of units.
Your �gsm� occurred 15 times out of 70, the SI unit g/m2 (with a superscript
2) occurred 13 times out of 70 (ouch!), but the most common was some form of
GSM with a frequency of 29 occurrences from 70 but also with the greatest
variations of form. It is very clear from these data that abbreviations are
constantly and randomly created, and that this can happen even at the same
paper suppliers for different product lines. It is also clear that jargon
creation is also at work here; people in the paper trade seem to want their
own units that are different from the units used in other companies and in
other industries.
>From these data I could not discern any 'industry standard' at work. One of
the issues that is obvious is that there is considerable confusion in the
paper trade as to what is the preferred unit and, indeed, what the unit
means. You can�t write �GSM: 80 Grains:� without a profound misunderstanding
of the quantity you are measuring, the unit and the relationship between
them. This morning when I asked the storeman which unit he preferred he said
(unprompted and immediately) �The little g with the slash and the m
squared�. I asked why and he replied �Because you know what they mean�.
World standards
One of the strengths of SI is that it is a world standard, for example g/m2,
always and everywhere, is the legally accepted symbol for the unit grams per
square metre.
Can the same be said for gsm, or is it language dependent? Do the same
initial letters apply in German, French, Thai, Chinese, or Japanese? Is the
unit gsm supported by international treaty or organisation?
Legal issues
Is Australia a signatory to any treaty that recommends the use of gsm? Is
the use of gsm supported by Australian trade legislation for use in legal
contracts within Australia? Is the use of gsm supported by Australian and
foreign trade legislation for use in legal contracts when an Australian
company trades internationally? I suggest that the answer to all three
questions is no.'
By the way, a strict - SI - reading of 'gsm' reads 'gram second metre',
whatever that might measure.
Cheers,
--
Cheers,
Pat Naughtin
CAMS - Certified Advanced Metrication Specialist
- United States Metric Association
ASM - Accredited Speaking Member
- National Speakers Association of Australia
Member, International Federation for Professional Speakers
on 2001/05/14 06.31, [EMAIL PROTECTED] at [EMAIL PROTECTED] wrote:
> On Sun, 13 May 2001 20:49:55 +0100, "Mark Halsall" wrote:
>
> I hadn't really considered paper mass until now, but I just bought a
> ream of paper for my printer and thought I'd work it out.
>
> By my calculation a ream (ie 500 pages) of paper (A4) at standard 80
> g/m2 turns out to be exactly 2.5 kg - a useful perceptual measure I
> think.
>
> Regards,
> Mark
>
> #>- Subscription Options; -<#
> #>- http://list.to/srv/SubOpt?id=_3rQpacvqSYv6W4P6sbWxR8DJ5EplT5l6?= -<#
>
> UK Metrication Association
> http://www.metric.org.uk
> Messages posted on the list should not be reproduced without permission.
> Mailinglist WWW Archive;
> http://list.to/srv/WebArchive?id=_y+MuWw+gZOn1ZWUJ6zhcYw=
>
> Advertisement;
> _________________________________________________________________________
> Website content enhancement for list.to is provided by dataradar.com
> Data harvesting, content enhancement, advertising targeting and more...
> See us at... http://www.dataradar.com
>
>
