Thirty minutes into Malcolm X, the title character (Denzel Washington) concludes a run-in at a bar by smashing a bottle against a man’s head. The victim is led away, cradling his bloodied ear. But if you freeze the action on your VCR, you’ll find this sequence isn’t all it’s cracked up to be. Not only does the actor close his eyes and turn away just before contact, he reacts as if he’s been hit on the side of his head when the bottle actually strikes his right shoulder. The cheat demonstrates a basic truth of moviemaking: 100 percent realism is By No Means Necessary.