PAPER: from ulop.net

In light of frequent paper quality queires, i decided to post a definition of the various paper available today.

paper is defined by weight and paper size, according to the familiar ‘A’ and ‘B’ sizes of ISO 216. ISO paper sizes are all derived from a rectangle with the area of one square metre (A0 is 841x1,189mm). A sizes are intended to be the finished job sizes; RA sizes are to allow grip on the printing press; and SRA sizes allow for grip and bleed. B sizes are to cover oversize jobs.

In Europe, they use the familiar
grammes per square metre rule (gsm) to define a paper’s weight. In the

metric system, the weight or substance is expressed as gsm or gm/2. It is calculated by the physical weight of one sheet of paper measuring 1x1 metre. In reality, no one actually folds a sheet of paper that large to weigh it! It is generally measured using a scaled-down measure of 10x10cm. The thickness or caliper of a sheet of paper is often described as bulk. It is measured using a micrometer and expressed in microns. Things are different in the US, where paper is measured using imperial measurement in lbs, by thickness in thousandths of an inch.

Paper used for printing is usually between 60g and 120g. A ream of copy paper is usually around the 80gsm mark, while material heavier than the 160gsm mark is considered card.

Anything between 10-35gsm is considered tissue paper. After that, up to 70gsm is lighter textweight paper, with most printer and copy paper fitting into the medium textweight of up to 100gsm. Heavy textweight paper (also light cardstock) is between 100-120gsm, while regular cardstock is up to 150gsm, with heavy cardstock after that. Most art paper used for printing brochures and magazine covers is coated with china clay (kaolin). Matte or glossy finishes are also used inside high-quality magazines. Chromo paper is similar, but is only finished on a single side – it’s used for poster printing, for example. Cast-coated paper is a high-gloss paper where the coating has been allowed to harden while it’s up against a polished chrome surface. The level of gloss needed is highly dependent on the purpose of the paper.

Uncoated papers come in a wide variety of finishes and quality. They are often described as offset or cartridge papers. These are typically rougher and used for more general purposes, such as for envelopes and pads. Laser papers are generally smoother and designed to work well for office printing. Uncoated text and cover papers are usually of the highest quality, with excellent reproduction for brochure use, and will generally show brilliant results when printing solids and 4-colour imagery.Coated papers are produced by applying a coating mixture to china clay, chalk and latex. This can be done either on the paper machine (at the end of the drying process) or on a coating machine. Applying a coating has the effect of making a sheet smoother and more receptive to the ink, resulting in a technically superior printing surface. Matt-coated papers are produced by the application of the coating, which is then scraped off using a very sharp blade, leaving a smooth matt finish. Silk-finished papers are produced by slightly calendaring (polishing) the material using heat, pressure and polished rollers. High gloss papers – also known as art papers – are created by coating the paper, as with matt-coated paper, but then putting it under extreme pressure, a very high temperature and highly polished rollers.

source: www.computerarts.co.uk/in_depth/features..._to_grips_with_paper

unfortunately, with paper, like all products, you mostly get what you pay for. just because their weight label indicates they are the same, doesn't necessarily mean they will give you the same quality prints. ink on cheaper paper blots more than most higher priced ones, giving dull blurry prints.

you'll just have to compare them to see the difference, and make the best decision for you. ^^