Listed are five online resources on basic and extensive information about paper and the many types thereof:
http://www.biltpaper.com/atoz3.asp
http://www.rbms.info/committees/bibliographic_standards/controlled_vocabularies/paper/th343.htm
http://www.colorcopiesusa.com/all-about-color-printing/printing-paper.htm
http://www.greatschools.org/worksheets-activities/6063-different-types-of-paper.gs