When a director/producer plan to do an adaption of book, how much do you they pay the author
Take for example the Twilight franchise. How much do you pay the authors?
I think you need to be more specific. It's like asking how much does a boat cost. Some books, like the Harry Potter series, were obvious hits that could translate to film. On the other hand The Lord of the Rings and Dune, extremely popular in the 60's and 70's, had been considered unfilmable. Some still think Dune turned out to unfilmable.
There's a huge difference. Some authors get a flat fee, some authors (like J.K. Rowling) get a percentage and script approval.
They don't pay you anything if you don't know that the correct word is "adaptation."
Depends on what kind of fee the author's agent negotiates for the film rights.
They get a free medium Popcorn and Diet Coke at the Premiere!
I didn't feel the need to pay Art Spiegelman anything.