Many people call The Last Supper a fresco, which was tempera on wet plaster but according to Lisa Shea's website on DaVinci, he wanted to make his colors more vibrant and add his own flair. <img src="/images/graemlins/wink.gif" alt="" />
He used tempera plus oil painting on DRY plaster, which is why it has been crumbling ever since, so it truly is not "fresco" but fresco"like". And this is why Lisa says, "you can't believe everything you read on the web. <img src="/images/graemlins/smile.gif" alt="" />"
Trish