GSM and paperweight explained
Whether you’re ordering flyers, business cards, or any other commercial printing, we are going to ask you what GSM you want. If you’ve got no idea what GSM stands for, here is a very brief explanation.
What does GSM mean?
GSM stands for ‘Grams per Square Meter. It’s a measurement of paper quality which allows for printers to differentiate between varieties of stock depending on each customer’s preferences. As the name suggests, it tells you how much a square metre of the paper or card would weigh. Although everyone tends to think in terms of thickness, with premium print being on thicker paper, it’s a good means of standardising the business and making sure that customers know what they’re getting.
How does it work?
Here’s a basic translation of some of the most common paperweights.
- 350 to 400 GSM – This is what you might expect a good quality business card to be printed on.
- 170 to 250 GSM – Like a mid-market magazine cover.
- 130 to 170 GSM – A good quality brochures.
- 90 to 100 GSM – Mid-market magazine inner pages.
Coated and Uncoated Stock explained
Coating is used to finish paper and provide some added-value
Coating is a process by which paper or board is coated with an agent to improve brightness or printing properties. By applying PCC, china clay, pigment or adhesive the coating fills the miniscule pits between the fibres in the base paper, giving it a smooth, flat surface which can improve the opacity, lustre and colour-absorption ability. Various blades and rollers ensure the uniform application of the coating.
Different levels of coating are used according to the paper properties that are required. They are divided into light coated, medium coated, high coated, and art papers – art paper is used for the high quality reproduction of artwork in brochures and art books.
Not all paper is coated. Uncoated paper is typically used for letterheads, copy paper, or printing paper. Most types of uncoated paper are surface sized to improve their strength. Such paper is used in stationary and lower quality leaflets and brochures.
Types of Paper: Bond, Art & Board
Bond paper is a high quality durable writing paper similar to bank paper but having a weight greater than 50 g/m2. The name comes from it having originally been made for documents such as government bonds. It is now used for letterheads, other stationery and as paper for electronic printers. Widely employed for graphic work involving pencil, pen and felt-tip marker, bond paper can sometimes contain rag fibre pulp, which produces a stronger, though rougher, sheet of paper.
Art (Coated paper)
Coated paper is paper which has been coated by a compound to impart certain qualities to the paper, including weight, surface gloss, smoothness or reduced ink absorbency. Kaolinite or calcium carbonate are used to coat paper for high quality printing used in packaging industry and in magazines. The chalk or china clay is bound to the paper with synthetic viscofiers, such as styrene-butadiene latexes and natural organic binders such as starch. The coating formulation may also contain chemical additives as dispersants, resins, PE: to give water resistance and wet strength to the paper, or to protect against ultraviolet radiation.
Paperboard is a thick paper based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker (usually over 0.25 mm/0.010 in or 10 points) than paper. According to ISO standards, paperboard is a paper with a basis weight (grammage) above 224 g/m2, but there are exceptions. Paperboard can be single or multi-ply. Paperboard can be easily cut and formed, is lightweight, and because it is strong, is used in packaging. Another end-use would be graphic printing, such as book and magazine covers or postcards. Sometimes it is referred to as cardboard, which is a generic, lay term used to refer to any heavy paper pulp based board. Paperboard is also used in fine arts for creating sculptures.