A quick guide to paper and card
As a novice print-buyer, paper can be a daunting subject. There are coated papers; sometimes referred to as gloss, silk or matt art papers and uncoated papers which contain types such as bonds, offset and cartridge papers. In addition there are a whole range of specialist papers such as NCR (no carbon required self-carbonating paper), non-tearing and waterproof papers, metallic papers, textured papers, self-adhesive and colour-tinted papers and boards.
Coated papers such as Gloss, Silk or Matt have a special china clay coating which fills the pits between the fibres of the paper making it a smoother, flatter service which is gives better print quality. This also adds to the weight; typically a 100gsm coated paper would be much thinner than an 80gsm uncoated paper.
The weight of paper is defined in gsm (grams per square metre), so if a paper weighs 80gsm, then one square meter of it would weigh 80 grams. This is made a little more confusing by the fact that some materials are defined in microns (thickness) instead of weight.
Then of course, there are paper sizes. Generally referred to as A, SRA and B Sizes.
A sizes are common finished sizes such as the standard letter head size A4 (210mm x 297mm). The largest typical A size would be A0 841mm x 1189mm which is virtually one square metre of material. A1 is half of A0 at 841mm x 594mm, A2 is half of A1 at 594mm x 420mm, A3 is half of A2, right down to A8 which at 52mm x 74mm is 1/256 of A0.
SRA sizes and B sizes are larger versions of A sizes that are used by printers to accommodate such things as cutting marks, colour bars and bleed. This waste is then chopped off to leave a job at the appropriate finished size.