sources

http://homerepair.about.com/od/termsor/g/Pigment.htm
pigment paint info

http://www.britannica.com/EBchecked/topic/460189/pigment
encyclopedia entry on paint

http://www.alifetimeofcolor.com/study/g_tempera.html
art definition

http://www.newton.dep.anl.gov/askasci/chem99/chem99050.htm
chemistry of paint