From Scorsese on Scorsese by Martin Scorsese (edited by David Thompson and Ian Christie, London: Faber and Faber, 1989.).
"Travis really has the best of intentions; he believes he's doing right, just like St Paul. He wants to clean up life, clean up the mind, clean up the soul. He is very spiritual, but in a sense Charles Manson was spiritual, which doesn't mean that it's good. It's the power of the spirit on the wrong road. The key to the picture is the idea of being brave enough to admit having these feelings, and then act them out. I instinctively showed that the acting out was not the way to go, and this created even more ironic twists to what was going on. " p 62.
Below are the original storyboards for the shootout at the brothel as drawn by Martin Scorsese (pages 55-59). On the whole, the finished film follows them very closely with only minor changes as noted. I have highlighted one frame from each storyboard to compare with the corresponding shot in the completed film.
Upon hearing the gunfire Iris appears to be lifting only her head from the bed in the storyboard but in the film she sits up completely.
The shooter's gun is about two feet from Bickle's arm in the storyboard and his torso completely within the frame. In the film, he shoots from point blank range and only his arm is visible. When Travis fires back it appears in the storyboard that Scorsese planned to have his victim shot in the eye(?) but it's difficult to tell. He is shot in the forehead in the film.
Two reverses from the storyboard: In the first shot, Iris is on the left side of the room but in the storyboard she is on the right. In the second, Bickle puts his "gun" to his head with his left hand in the film, his right hand on the storyboard.
Scorsese does not elaborate in the book on the reason for any minor changes. Minor changes from storyboard to completed film occur regularly during the shooting process and many directors have been known to draw up a new storyboard during the shooting. Most of these changes probably occurred from necessity more than anything else. For instance, in the story board Scorsese has the shooter with glasses shot in the eye. Perhaps that is why he gave him glasses, to conceal the squib that would go off but it proved more difficult than thought so his forehead was used instead. When Bickle sits on the sofa in the film his right arm is bunched up against the corpse of one of his victims and so going with his left hand was probably just easier. And yet it created an iconic image: I cannot imagine Bickle's right hand at his head, it has to be the left.
Scorsese's storyboards confirm the importance of the director to the visual result of the film. True, a good cinematographer must still set up the shot, properly light it and make it work. But a good director has already shot the movie in his head and on paper before the camera ever rolls. Think of Orson Welles two masterpieces Citizen Kane and The Magnificent Ambersons. They each had a different cinematographer (Gregg Tolland on Kane and Stanley Cortez on Ambersons) and yet have remarkable visual similarities as well as visual flourishes not found in other Tolland or Cortez shot films. However, a director can have all the visual ideas in the world and without the right cinematographer those ideas may end up unrealized. Tolland and Cortez were brilliant cinematographers and had the talent to give Welles what he wanted. Just as Scorsese had Michael Chapman (Invasion of the Body Snatchers 78 and Raging Bull 80) help him create one of the most stunning climaxes to any film of the seventies. It was a final brutal entry into the world of Travis Bickle but without Scorsese's storyboards and Michael Chapman's camera work, it might have been just another shootout.