Oswald in the doorway: the blog of the Oswald Innocence Campaign, by Ralph Cinque

One cannot exaggerate the importance that the Stemmons freeway sign has in the Zapruder film. It is like the magician's curtain. It is the division between the "before" and "after." And I have no doubt that the sign was enlarged, manipulated and enhanced. 

Here is a comparison of the sign in Zapruder with the real sign.

In Zapruder, the sign is larger, and it is much more pervasive. It provides more coverage. And one way they got it to provide more coverage was to make the angle of it different. It faces the street more in Zapruder.

They wanted everything to happen behind that sign, and by everything I mean the action of the so-called Single Bullet that supposedly traversed Kennedy and Connally before settling in Connally's thigh before it "fell out" while he was on a stretcher at Parkland Hospital

In the Zapruder film, the story is that Kennedy reached the sign unharmed, however, it does contain a glitch because it shows Kennedy as having stopped waving before he reached the sign. 

Now, if he wasn't harmed, why would he do that, stop waving and put his hand over his face? He was a politician out in public, and this was a political trip. He wouldn't have done that. I suspect that hand over his face is fake, but, he did stop waving, as we can see in the Croft and other photos. And the reason he stopped waving is because he was shot. And notice how fake the hand looks. If he brought his right hand up to his face, the thumb would be on the outside. Try it yourself. 

You see? It's just another crude alteration.