Editing Paper (section)

==Types, thickness and weight==
[[File:Coloured, textured craft card.jpg|thumb|right|Card and paper stock for [[crafts]] use comes in a wide variety of textures and colors.]]

The thickness of paper is often measured by caliper, which is typically given in thousandths of an inch in the United States and in micrometers (µm) in the rest of the world.<ref>{{Cite web|url=http://www.casepaper.com/calc_chart_caliper.htm|title=Paper Thickness Chart|website=Case Paper|language=en-US|access-date=2017-05-27}}</ref> Paper may be between 0.07 and 0.18 millimetres (0.0028 and 0.0071 in) thick.<ref>{{Cite web|url=http://hypertextbook.com/facts/2001/JuliaSherlis.shtml|title=Thickness of a Piece of Paper|last=Elert|first=Glenn|website=The Physics Factbook|language=en|access-date=2017-05-27}}</ref>

Paper is often characterized by weight. In the United States, the weight assigned to a paper is the weight of a ream, 500 sheets, of varying "basic sizes", before the paper is cut into the size it is sold to end customers. For example, a ream of 20&nbsp;lb, {{convert|8.5|x|11|in|mm|0|abbr=on}} paper weighs 5 pounds, because it has been cut from a larger sheet into four pieces.<ref>{{Cite book|url=https://www.worldcat.org/oclc/851074844|title=The Hammerhill guide to desktop publishing in business|last=McKenzie|first=Bruce G.|date=1989|publisher=Hammerhill|isbn=9780961565114|oclc=851074844|page=144}}</ref> In the United States, printing paper is generally 20&nbsp;lb, 24&nbsp;lb, or 32&nbsp;lb at most. Cover stock is generally 68&nbsp;lb, and 110&nbsp;lb or more is considered card stock.

In Europe, and other regions using the ISO 216 paper sizing system, the weight is expressed in grammes per square metre (g/m<sup>2</sup> or usually just g) of the paper. Printing paper is generally between 60&nbsp;g and 120&nbsp;g. Anything heavier than 160&nbsp;g is considered card. The weight of a ream therefore depends on the dimensions of the paper and its thickness.

Most commercial paper sold in North America is cut to standard paper sizes based on customary units and is defined by the length and width of a sheet of paper.

The ISO 216 system used in most other countries is based on the surface area of a sheet of paper, not on a sheet's width and length. It was first adopted in Germany in 1922 and generally spread as nations adopted the metric system. The largest standard size paper is A0 (A zero), measuring one square meter (approx. 1189 &times; 841&nbsp;mm). A1 is half the size of a sheet of A0 (i.e., 594 mm &times; 841 mm), such that two sheets of A1 placed side by side are equal to one sheet of A0.  A2 is half the size of a sheet of A1, and so forth. Common sizes used in the office and the home are A4 and A3 (A3 is the size of two A4 sheets)<ref>[https://unsharpen.com/paper-sizes/ Paper Sizes Explained]</ref>.

The density of paper ranges from {{convert|250|kg/m3|lb/ft3|0|abbr=on}} for tissue paper to {{convert|1500|kg/m3|lb/ft3|0|abbr=on}} for some speciality paper. Printing paper is about {{convert|800|kg/m3|lb/ft3|0|abbr=on}}.<ref>{{cite web|url=http://www.paperonweb.com/density.htm|title=Density of paper and paperboard|publisher=PaperOnWeb|accessdate=31 October 2007}}</ref>

Paper may be classified into seven categories:<ref>{{Cite book|url=https://www.worldcat.org/oclc/959020143|title=The Thames and Hudson manual of bookbinding|last=Johnson|first=Arthur|date=1978|publisher=Thames and Hudson|location=London|oclc=959020143|language=en}}</ref>

*''Printing papers'' of wide variety.
*''Wrapping papers'' for the protection of goods and merchandise. This includes wax and kraft papers.
*''Writing paper'' suitable for stationery requirements. This includes ledger, bank, and bond paper.
*''Blotting papers'' containing little or no size.
*''Drawing papers'' usually with rough surfaces used by artists and designers, including cartridge paper.
*''Handmade papers'' including most decorative papers, [[Ingres paper]]s, [[Japanese paper]] and [[tissue paper|tissues]], all characterized by lack of grain direction.
*''Specialty papers'' including cigarette paper, toilet tissue, and other industrial papers.

Some paper types include:
*Bank paper
*Banana paper
*Bond paper
*Book paper
*Coated paper: glossy and matte surface
*Construction paper/sugar paper
*Cotton paper
*Fish paper (vulcanized fibres for electrical insulation)
*Inkjet paper
*Kraft paper
*Laid paper
*Leather paper
*Mummy paper
*Oak tag paper
*Sandpaper
*Tyvek paper
*Wallpaper
*Washi
*Waterproof paper
*Wax paper
*Wove paper
*Xuan paper