What make-up technique was used to preserve Jack Nicholson's grin as the Joker on the original Batman movie? ?

Question

For Jack Nicholson's Joker grin, were prosthetics used? Was his face freeze dried as original rumor has it?

Answer 1

yeah, i don't think freeze drying is even possible...

it would cause damage to the skin, not to mention hurt like h**l...

it would definately be prosthetics and make up.

Answer 2

I've never heard that ridiculous rumor.  

I'm assuming it was a type of foam glued to his face, then they painted make-up over it.