I know that every case can be different, but it seems like there should be a standard split between the author and the illustrator of a children's book. Does anyone know?
I am a children's book illustrator. Thom is right 50:50 or for heavily illustrated picture books 60:40. When it comes to the advance, the illustrator usually gets more because it will take them 3 to 8 months to finish illustrations for the book. They need something to live on while they are working.