http://ameblo.jp/gsc-mikatan-e/entry-10736119736.html
http://mikatan.goodsmile.info/en/2011/03/18/mikatans-factory-field-trip-part-4/
Mikatan did a series of articles on how these figurines are painted, some parts are machine painted, some are hand painted. Nowdays lots of small parts are done with 3D printers too, the books and that chair of this Tharja figurine is probably done with a 3D printer (maybe not the chair, but the books would definitely be a pain to do without 3D printers).
That's really interesting. I wonder if the march of 3D printer technology will put these people out of a job. I would think the higher end, more premium figures are hand painted.