But can you tell me why removing a frame from the Zapruder film would not work?
Seems to have worked just fine.
Lets say the limo slowed to 2 mph. The Z film has it slowing to 8 mph. To make the limo appear to go 8 mph they would need to remove 3 out of every 4 frames. That would mean through that part of the film the people in the limo and Miss Foster would all speed up x4. By around frame 350 they may have been doing 4mph so they would need to take out every other frame at that point. So we would see Malcom Summers thrust himself to the ground at twice the natural speed.
This would have been a complicated process using matte shots for the background and for the occupants of the limo to keep their action from doubling and maybe quadrupling in speed which would be obvious compared to their movement prior to and after the limo stop.
The only alteration that would have been fairly straight forward would have been masking the hole in the back of the head and the debris that came from it. People claim that they would have had to do that on the tiny 8mm film itself but that is not true. The 8 mm film strip is magnified 60 times when projected onto a screen at 3 feet wide so you have room to work without causing it to look all blurry. So you photograph a frame in 50mm then edit the actual photograph and then re film it through the original camera one frame at a time. That would allow the film to show the 8mm film grain it should have.
Both John and Chris do not understand that simply removing frames won’t work. Why? Not so much because it would show impossible speeds but because it would show impossible accelerations.
As it turns out, by a coincidence, if the limousine is moving “x” mph, it will advance “x” inches with each Zapruder frame. So, at 8 mph, it will advance 8 inches with each Zapruder frame.
Let’s say the original film showed the limousine moving at 8 mph. The limousine advanced
| | first | second | third | fourth |
| distance: | 8 inches | 8 inches | 8 inches | 8 inches |
| average speed: | 8 mph | 8 mph | 8 mph | 8 mph |
So, we now decide to simply snip out the second frame, giving us the following:
| | first | second | third |
| distance: | 8 inches | 16 inches | 8 inches |
| average speed: | 8 mph | 16 mph | 8 mph |
So, it looks like the limousine was going 8 mph, it suddenly advanced 16 inches, indicating a speed of 16 mph, then resumed it’s 8 mph. What’s the problem? The problem is the limousine was going at a steady 8 mph, then suddenly accelerated to 16 mph. To do this it would have to accelerate to 24 mph, then decelerate to 8 mph, all within 55 milliseconds, to end up with an average speed of 16 mph.
Can real world automobiles do this? No. Not even close. Typically, an automobile can perhaps accelerate or decelerate at half a G. At half a G, the automobile can gain or loss 11 mph in one second. So, it can go, with maximum braking, from 55 mph to 0 mph in 5 seconds. Maximum acceleration rates are generally not quite as good so a large heavy limousine would have difficulty going from 0 mph to 55 mph in 5 seconds.
So, if the limousine was going a steady 8 mph, and started accelerating as fast as it could, the sort of acceleration needed to go from 0 mph to 45 mph in 5 seconds, it would look like this:
| distance: | 8.0 inches | 8.5 inches | 9.0 inches | 9.5 inches | 10.0 inches | 10.5 inches | 11.0 inches | 11.5 inches |
| average speed: | 8.0 mph | 8.5 mph | 9.0 mph | 9.5 mph | 10.0 mph | 10.5 mph | 11.0 mph | 11.5 mph |
It would take about 16 Zapruder frames, almost a second, for the limousine to accelerate from 8 mph to 16 mph.
So, removing a frame would give the appearance of impossible acceleration. Removing 3 frames in a row, as Chris was suggesting, makes the problem much worse.
Now, there is one way around this. Don’t remove a frame here or there, but do so in a systematic fashion. Remove every other frame in the entire Zapruder film. So instead of the limousine appearing to vary speeds between 4 mph to 18 mph, it would appear to vary between 8 mph to 36 mph. And this would also make Clint Hill’s top running speed of 8 mph appear to be 16 mph. I don’t think anyone really goes along with this removing every other frame theory. But it is the only possibility that remotely works.
If only every fourth frame was kept, something like Chris suggested, everyone seen jogging into position to see the limousine would appear to move with the ludicrous speed of a Keystone Cop.
Essentially, to modify the Zapruder film, in a way that can avoid obvious tampering, is for every frame that is removed, a new frame must be inserted. This can either be a totally new frame, or a modification of the old frame. One cannot simply remove a frame. Nor insert a totally new frame.
But what surprises me, with the Zapruder Alteration theory going on for 25 years now, is how common it is for people to suggest how simple modifying the Zapruder film would be, to just remove a frame here or there. It does not seem to occur to anyone that this would not result in impossible speeds, but would result in impossible accelerations. All a person would need to prove the Zapruder film was altered is to spot a sudden “jump” forward by the limousine whenever a frame is removed.
Question:
How is it, that after 25 years, Zapruder Alteration Theorists have not figured this out on their own by now? 
