Thanks Jeremy, that is what I thought. Ply is used as a term of
thickness for mount board though rather than gsm or it’s imperial
equivalent. Presumably this is because it’s made up of layers? I brought
the question up as Eric mentioned Strathmore Artist Drawing paper 1 ply. I guess
that as a measure of thickness/weight it’s meaningless and really a
marketing term?
Best,
John.
From: Jeremy Moore
[mailto:jeremydmoore@gmail.com]
Sent: 15 January 2009 15:52
To: alt-photo-process-l@usask.ca
Subject: Re: Albumen paper and ply
No, because ply is the number
of layers of paper and gsm is the weight of the paper. Each ply can be whatever
weight you want, for instance, think of toilet paper: 1-ply is just one layer
of toilet paper and 2-ply is two layers together. You may be thinking of the
conversion between gsm and lb/sq.in.: 1 lb/sq.in. is about 704 kg/sq.meter and therefore 80 pound
is roughly equivalent to 216.5 gsm.
-jeremy-
On Thu, Jan 15, 2009 at 9:39 AM, John Brewer <john@johnbrewerphotography.com>
wrote:
Thank-you Eric.
Is there a direct conversion
from 'ply' to gsm?
Regards
John.