With a particular emphasis on Harry Potter, LOTR and the Narnia books and movies.
1. You can always add scenes that weren’t in the book.
Remember the Burning of the Burrow scene in Harry Potter and the Half Blood Prince? Or even the Susan-Prince Caspian love angle in The Chronicles of Narnia: Prince Caspian? No fan of the original source work would have tolerated those ‘aesthetic additions’. But ah well, you get the point. If Mr X wasn’t at a particular place in the novel, well who cares? Make Mr X go where no man has ever gone before – and bear the consequences.
2. You can cut out sequences from the books seemed very fine and dandy for that kind of medium, but appear too slow and unbearable in films.
For example, where was Tom Bombadil when Frodo and the gang left Hobbiton in The Lord of the Rings: The Fellowship of the Ring? He remained in the books, but the films didn’t even keep his shadow. Reason? Once you build up pace, with all the Ringwraiths chasing Frodo and his friends, how in the world can Tom Bombadil shield them? A dramatic scene will lose its effect if things suddenly come to a standstill. But try explaining that to fans of the original source work who may not like your ‘cut scenes’ policy for dramatic effect.
3. You can change characters from the books and make them the way you want.
Dorian Gray anyone? Ben Barnes is black-haired in the movie, but our book protagonist is blonde-haired. Hermione has buck teeth in the Harry Potter books but we wouldn’t have had fashionista Emma Watson if she was dressed the same way too. We have Arwen (not Glorfindel) rescuing Frodo in The Fellowship of the Ring, giving us a taste of girl power in a series that barely has any women. Can’t take in all the changes? Well good luck getting your point across.
4. Make a character say something he/she wouldn’t have said otherwise. Prince Caspian, people?
“Prince Caspian: I wish we could have had more time together.
Susan Pevensie: We never would have worked, anyway.
Prince Caspian: Why not?
Susan Pevensie: Well, I am 1300 years older than you.”
That says it all – completely cringe-worthy.
5. Play with time.
I don’t mean the literally ’play with time’ sequence that happens in Harry Potter and the Prisoner of Azkaban, when Harry and Hermione use the time turner. Or do I? You can always jump a few years forward, or eliminate a few years in between or completely create a new year. Your choice. Frodo never set out from Hobbiton almost immediately after Bilbo’s party. Prince Caspian was around 14/15 when he had to flee from his Uncle Miraz. And no, he wasn’t a 20-something handsome Hollywood hunk. But if you’re a purist, I guess you have to swallow the ‘creative liberties’.
And after all this – if you really want to know how to change source material and create your own story, refer to Disney’s animated films over the years.