A few weeks out from production beginning on the pilot, "Arrow" producer Greg Berlanti tells Digital Spy that the upcoming "Flash" spin-off series will have a quite different tone to "Arrow" in both the main character's outlook and the show's overall feel:
"Barry (Grant Gustin) is different from Oliver (Stephen Amell). He's a man of science and has more of a sci-fi bent, whereas Arrow has a bit more of a crime bent.
We often talk about how Oliver comes off like a pessimist, but deep down he's an optimist and has hope. Barry lost his mother at a very young age, his father was sent to prison for murdering his mom, he went through a lot of stuff - on the surface he's bubbly and upbeat and seems like an optimist, but deep down maybe there's no hope left.
So they're a really nice contrast to each other and the show functions in that way, I think. Certainly in the pilot script Barry has an effervescence and a lightness, but there's still a dark well beneath that."
Berlanti confirms that S.T.A.R. Labs will be an active part of the show. Berlanti also says that in the highly unlikely prospect that "Flash" doesn't get a series order past the pilot, they'd try and get Grant Gustin's Barry Allen back as much as possible.
"Fingers crossed we don't screw it up and he gets his own show! If he didn't, I don't think we would ever want to let Grant go. He's too valuable. That would be our hope, I think - no matter what, to keep Barry part of the universe."