The paper must fit the brief for the job, and the finish should also be appropriate to the content. For good-quality colour halftone reproduction, a coated stock (made with mineral fillers to create a very smooth surface) would normally be used, although some very fine uncoated papers now boast excellent colour quality. The weight of paper is classified by grams per square metre (gsm or gm2), a standard sheet of copier paper weighing 90 gsm. The impact of a prestigious catalogue could be increased by using 150 or 200 gsm. Generally, heavier papers or art boards are thicker than light ones, but the density and type of fiber will have an effect on thickness (bulk). Glossy art paper can feel thinner than an uncoated stock of the same weight, so it may be necessary to increase the weight when choosing a gloss finish. Be careful of ink showing through some lightweight papers. If a brochure needs to be mailed, the weight of the stock will affect the cost of postage.