The thickness of a sheet of watercolor paper is measured by weight. The greater the weight, the thicker the sheet. It is measured either in pounds per ream (lb) or grams per square meter (gsm). This scale may be helpful to you:
|22″ x 30″ (Sheet size)|
|2292 (Sq. ft./ream)|
|GSM (metric)Grams per square meter||Pounds|
GSM = Grams per square meter.
For a 300 gsm paper, this means that if you cut a sheet of paper 1 meter long by 1 meter wide, it will weigh 300 grams (about 2/3′s of a pound)
Ream = 500 sheets of paper Since the paper and printing industry began, different businesses used different ream sizes due to the application they were making.
For example 500 sheets of watercolor paper 22″x30″ may weigh 90 lb ( which is 190 gsm ).
The confusing part is when the paper gets different sizes then 22″x30″.
I have a paper 26″x40″, which is 356 gsm. So you would see that it is also about 167 lb. for the size 22″x30″. But would it be the same pound weight for 26″x40″? I promise to solve this mystery in the closest time.
I used a part of the chart, designed by Museo Fine Art