Tools of Characterization
Characterization in Harry Potter and the Half-Blood Prince
Speech and Dialogue
Sometimes you just have to learn about a character from the horse's mouth, right, Shmoopers? We definitely learn a lot about Harry's crowd from the way they talk to each other.
Take our "friend" Draco Malfoy, for example. When he catches Harry eavesdropping on his conversations and decides to punish him, he slips in a crack about the death of Harry's mother:
MALFOY: Didn't Mummy ever tell you it was rude to eavesdrop, Potter? Petrificus Totalus! Oh yeah, she was dead before you could wipe the drool off your chin.
Lovely. Well, Draco isn't the nicest of guys, so making fun of a guy for being an orphan is so not beneath him.
Actions
How people act is pretty important to figuring them out, and Professor Slughorn gives us a prime example. He definitely wants to be seen as a good guy...but is he really as innocent as he's pretending to be?
Well, he's definitely been lying about his history with Voldemort, so we think the answer is probably "Not so much." Dumbledore knows that Slughorn is withholding information about a conversation he had with young Voldy back in the day to save face, even though that information could be crucial to defeating the Dark Lord. We mean...come on, dude.
Yup, that's right: saving face is (at least at first) more important to Slughorn than defeating the most evil, no-good wizard of all time. Says a lot, doesn't it?
Direct Characterization
Well, we get a lot of direct characterization in this particular film, especially when we're dealing with Snape. Everyone seems to have their own opinion about whether Snape is loyal to Dumbledore/the Order of the Phoenix or...not.
On the Dark Side, Snape definitely has his doubting Thomases (or Thomasinas). When Narcissa Malfoy goes to see Snape for help, for example, her sister Bellatrix is super against it. She flat-out says the dude isn't loyal:
BELLATRIX: Cissy, you can't do this! He can't be trusted.
NARCISSA: The Dark Lord trusts him.
BELLATRIX: The Dark Lord is mistaken.
And Snape has doubters and defenders on the other side as well. When Harry is telling Lupin about a conversation he overheard about Snape's activities on the Dark Lord's behalf, Lupin kind of sticks up for Snape:
LUPIN: Has it occurred to you, Harry, that Snape was simply pretending to offer Draco help so he could find out what he was up to?
He's the most optimistic werewolf we know, that's for sure.
Anyway, we get a few different perspectives on Snape through snippets of dialogue...unfortunately, only Snape knows for sure which side he's on. And he's not letting us in on the secret just yet.