What type of references and rules do other people use for wrinkles and flesh folds? Hiring a model isn't really an option for me. The more exaggerated the examples, the better.
So far I've been relying mainly on the illustrations of Rubens and looking up illustrations of various types of tchthyosis (when skin is hardened and scaly like that, it usually makes wrinkles really prominant). Aside from that I've merely been applying techniques used for drawing wrinkles in clothing, like those by Hogarth and Jack Hamm. Many wrinkles in the human body seem to follow the same rules, but I feel like I'm missing a pretty big part of the picture.
Any suggestions would be appreciated.
Well, no one replied, but I thought I'd share some of my findings:
Someone on irc recomended the sculpture series from gnomon, are they any good? He also pointed me to a pretty awesome royalty free image database; http://www.corbis.com. I've been able to find some really excelent images on that site of tribe people from Africa and Asia and stuff that have some really incredibly developed skin wrinkles, really perfect examples. So leathery that you'd almost think it were makeup.
Also, check out the sculptures by Evan Penny; http://www.evanpenny.com/slide_figures.php. Really great examples of exaggerated skin detail.
I also realised that the thread title was kind of ambiguous and might have implied I had found a good reference or something. I apologize about that.
I think i've more or less got what I need, but more examples would be welcome.
edit2: looks like I can't edit the thread title, if a mod happens to notice I'd appreciate if they could edit it for me. If not, no big deal.