A Guide to Card and Paper Weight and Thickness.
UK Card Crafts Card, paper & acetate products tend to be sold by their weight or thickness.
The weight of card and paper is measured in grams per square metre, or gsm for short. This measurement may also be written as g/m² and may be referred to as Grammage. Standard office paper weighs 80 grams per square metre. Since 16 sheets of A4 paper will fit onto 1 square metre of paper, a single A4 sheet measures 1/16 of the weight of 1 square metre. It therefore weighs 5 grams.
It’s important to remember that card and paper are able to absorb water. In the winter, paper products tend to suck water out of the air and this means that they become slightly heavier in weight. In the summer, paper products tend to lose water (dry out) and this means that they become slightly lighter in weight. If you have wooden doors in your home, you will have noticed that that they absorb water and swell up in the heat of the summer, making them more difficult to open and close. It’s the same with card and paper – they swell up too! As such, you may notice a difference in the weight of your paper products at different times of the year.
The thickness of Acetate is measured in microns, where 1,000 microns is equal to 1 millimetre. The thickness of acetate products may also be known by the name of caliper. To work out the thickness of acetate, you will need a tool known as a micrometre. A micrometre will provide you with the exact measurement of your product in microns. Card and Acetate used for arts and crafts can be found to be of thicknesses of between 200 and 500 microns (0.2 and 0.5 millimetres). Card thicker than 500 microns is usually made by laminating two or more sheets of card together. At UK Card Crafts and many other craft suppliers sell card by gsm but this is not the thickness remember, it's the weight.
Hope this guide has helped with regards to Card, Paper and Acetate weights and thicknesses.