Editing Pixel density (section)

== Metrication ==
{{see also|dots per centimetre}}

The digital publishing industry primarily uses pixels per inch but sometimes pixels per centimeter is used, or a conversion factor is given.<ref>{{cite web| url=http://www.washington.edu/accessit/webdesign/student/unit4/module2/web_graphics_basics.htm| title=Web Graphics Basics}}</ref><ref>{{cite web| url=http://www.utads.com/ad_specs/glossary.html| title=Utads.com Glossary of Terms| access-date=2011-03-22| archive-date=2012-09-28| archive-url=https://web.archive.org/web/20120928033128/http://www.utads.com/ad_specs/glossary.html| url-status=dead}}</ref><ref>{{cite web|url=http://www.monarda.se/extra/ppi-test/ppitest_english.htm|title=Resolution, dpi and ppi|access-date=2011-03-22|archive-date=2012-08-10|archive-url=https://web.archive.org/web/20120810234045/http://www.monarda.se/extra/ppi-test/ppitest_english.htm|url-status=dead}}</ref>

The [[Portable Network Graphics|PNG]] image file format only allows the meter as the unit for pixel density.<ref>{{cite web| url=http://www.w3.org/TR/PNG/#11pHYs| title=PNG file format, pHYs chunk}}</ref>