Choosing the right paper stock for your job is an important decision, on top of whether you want coated or uncoated you also need to choose the paper weight, or the GSM.
GSM is the definitive and universal measure of the weight of paper. It stands for Grams per Square Metre and comes from the actual weight of a piece of the paper cut to 100cm x 100cm. Even if that paper is cut down to a business card size the GSM will remain the same.
The lower the GSM, the thinner and lighter the paper, for example newspapers are around 55gsm as they are designed to be folded easily and only have a short life span. The higher the GSM, the heavier and thicker the paper. For example a business card needs to be more durable, so is likely to be printed on stock of around 350gsm upwards.
The GSM and the thickness are slightly different measurements and depend on the surface finish of the paper. For example, an uncoated 300gsm will have a thickness of around 350microns, whereas a 300gsm silk will have a thickness of only 280 micron. Coated papers are thinner because the clay coating is adding weight, rather than thickness, and in addition they are ‘polished’ to give their sheen, which in turn compresses the fibres and makes the paper a little thinner.