Re: [Origami] GSM vs LBS and variations. Help!

[kdiannestephens]

In searching online, I find the metric (gsm) notation to be consistent, but
I'd like to be able to do a conversion to foldable paper in LBS units.
Can someone explain how lbs associate to gsm?: Thanks! Rob


Here is a link to a conversion calculator and  the related formulas
http://okpaper.com/calculators/lbs-to-gsm
OriFUN to all
Dianne

Re: [Origami] GSM vs LBS and variations. Help!

[leslie cefali]

> On Jan 11, 2016, at 3:26 PM, Rob Hudson  wrote:
> 
> Can someone explain how lbs associate to gsm?:

Personally I like to use 24 lb. text weight over 20 lb. especially for 
modulars. I find the tension is a better with the very slightly thicker 24 lb.
I do not fold 60lb.  I find that too thick. It is like a light weight 
cardstock, which I do not find good for origami. 

They say 60 lb is cover weight.
90 lb is cardstock. 

Leslie

I also found a conversion chart at coastal print.com, though I am not sure if 
is makes it more confusing or if it is helpful.

Re: [Origami] GSM vs LBS and variations. Help!

[Anna]

2016-01-11 22:26 GMT+01:00 Rob Hudson :
> Can someone explain how lbs associate to gsm?:

Basically they don't. The gsm are grams per square meter and therefore
give you the density of the paper.

The lbs are the pounds per ream. A ream is (most often but not always)
500 standard-sized sheets, and different types of paper have different
standard sheet sizes. So this measurement unit is nuts, because it
tells you exactly nothing about the paper. No idea why it is still
used, must have something to do with wrong ideology.

On this page you can find a converter that takes the size of the paper
into account to convert to gsm:
http://www.stillcreekpress.com/paper-weight-conversion-tool/

Nice Greetings

Anna from Vienna, Austria

Re: [Origami] GSM vs LBS and variations. Help!

[Anne LaVin]

On Tue, Jan 12, 2016 at 10:55 AM, Anna  wrote:
>
> 2016-01-11 22:26 GMT+01:00 Rob Hudson :
> > Can someone explain how lbs associate to gsm?:
>
> Basically they don't. The gsm are grams per square meter and therefore
> give you the density of the paper.
>

Technically this is not exactly density, but, having units of mass per unit
area, is a property called "grammage":

 https://en.wikipedia.org/wiki/Grammage

(Proper density would be mass per unit volume. There is, apparently,
something called "area density" which exists for 2-dimensional objects...
and paper is thin, but not quite THAT thin...)

> The lbs are the pounds per ream. A ream is (most often but not always)
> 500 standard-sized sheets, and different types of paper have different
> standard sheet sizes. So this measurement unit is nuts, because it
> tells you exactly nothing about the paper.

This entry at Wikipedia:

  https://en.wikipedia.org/wiki/Paper#Types.2C_thickness_and_weight

has some useful tidbits including reference to the oddness with US paper
"weights":

"In the United States, the weight assigned to a paper is the weight of a
ream, 500 sheets, of varying "basic sizes", before the paper is cut into
the size it is sold to end customers."

And I have to agree with Anna, this is pretty crazy! I can't quite imagine
why anyone let this go on for so long and didn't find a way to standardize.
I suspect anyone in the trade just learns what the weights mean for all the
different kinds of papers, and that if one needs to be absolutely
unambiguous, one talks about grammage!

The "Grammage" page goes into some more detail on it, and has a chart with
the basis weights of different kinds of US papers, for reference.

Anne