How long does it take to alter hundreds of frames of film?

[Jack Trojan]

Jack does not understand simple Physics.

I'm a physicist. 

The limousine can only slow down so much. It can only lose about 0.5 foot per second per frame.

snip..

Are you referring to the jump cut at the turn onto Elm? I agree that from all accounts the limo had to almost stop to navigate the turn, which is probably why it was cut wholesale from the film. Pls explain the splice at frames 154-158:




But I was referring to the head shot which is more complicated to speed the film up but easy peasy nonetheless. An optical printer can quickly decimate frames to smoothly speed up the limo enough to cover up a "near" stop. If you want to do this right you must redo your calculations to determine the frame frequency/de-acceleration and decimate frames accordingly.



Note that the "speed" of the limo is in photo-units. Track the rotation of the tires and their circumference for a photo-unit -> speed conversion. When I did this I found the limo slowed down to ~7 mph. Speeding up the limo any more than that would also speed up bystanders actions as well, which would raise suspicions. I am not convinced that the limo was sped up in the darkroom, but it certainly could have been done easy peasy. The real question is why did it slow down at all? And why did it slow down just before the head shot? It caused the trailing motorcycles to make complete stops and gave Clint Hill a chance to climb aboard.

Lastly, I have a problem with the following clip of frames 317 to 320:



This animated GIF is depicted in real time. All the motion seen in the limo happened in less than a blink of the eye (.17 secs). In particular, note how quickly William Greer turned face front after applying the breaks and looking back at JFK just before the head shot. Looks like it is missing a couple of frames to de-emphasize that Greer hit the brakes hard enough to throw Kellerman forward, almost into the dashboard.

Given the Z-film was clearly modified by the FBI and as far as anyone knows they still have the original film, how can anyone look at a copy of the Z-film and claim the original had not been altered?

[Chris Davidson]

Close to the 154-158 span

CE884 entries for Z161-z166

Using the lightpost and CRB corner from the extant Z background, plotting the limo via the WC final plat, the speed of the limo equals 13.44mph.

13.44 x 1.47(1mph) = 19.7568 ft per sec

19.7568 / 18.3fps = 1.0796 ft per frame

5 frames (z161-z166) x 1.0796 ft per frame = 5.4ft traveled

CE884 states .9ft traveled for 5 frames

6frames x .9ft (distance given for 5 frames traveled CE884) =5.4ft

CE884 distance reflects 1 frame traveled at .9ft with the distance of 5 frames traveling @ 13.44mph, missing.

[Chris Davidson]

Limo Speed from CE884 Z161-z166:

18.3frames/5frames = 3.66 x .9ft = 3.294ft per sec / 1.47 = 2.24 mph

13.44mph - 2.24mph = 11.2 mph = Shaneyfelt

Mr. SPECTER. Is that a constant average speed or does that speed reflect any variations in the movement of the car?
Mr. SHANEYFELT. That is the overall average from 161 to 313. It does not mean that it was traveling constantly at 11.2, because it was more than likely going faster in some areas and slightly slower in some areas. It is only an average speed over the entire run.

[John Iacoletti]

Jack does not understand simple Physics.

I'm a physicist. 

[Chris Davidson]

Limo Speed from CE884 Z161-z166:

18.3frames/5frames = 3.66 x .9ft = 3.294ft per sec / 1.47 = 2.24 mph

13.44mph - 2.24mph = 11.2 mph = Shaneyfelt

Mr. SPECTER. Is that a constant average speed or does that speed reflect any variations in the movement of the car?
Mr. SHANEYFELT. That is the overall average from 161 to 313. It does not mean that it was traveling constantly at 11.2, because it was more than likely going faster in some areas and slightly slower in some areas. It is only an average speed over the entire run.

One other confirmation is Myers multi film sync project.

Once again, when plotted the limo travels 12.03 mph from z149-161 and 13.44mph from z161-z172.

The average between those two equals 12.735mph.

Myers has it traveling 10.5 mph between z150and z175.

The difference being 12.735mph - 10.5 mph = 2.235mph equals the previous difference (2.24mph) listed.

Myers 25 frame span = 25/18.3 = 1.366.... sec

1.366...sec  x 3.294ft per sec(2.24mph) = 4.5ft = 5frames at .9ft per frame

So 5 frames @ 13.44mph = 6 frames @ 11.2mph in terms of distance.

And, .9ft per frame = 11.2mph @ 18.3Frames per sec.

[John Mytton]

I already replied to this thread but it got wiped out by the LNers because I was getting too close to home.   

Chris Davidson is on the right track. There are only 2 questions needed to be answered to resolve this one:

1) Where is the "original" Z-film? Life got a COPY.
2) Why was the film "edited"?

There were at least 2 splices in the film, which the FBI must have created and they removed an entire section of the turn onto Elm. Zapruder said he never recalled letting his finger off the trigger at any time after he started filming. So why was this footage removed? And why are there splices in the film? And most importantly, where is the original film and why did the FBI keep it?

Any editing done to the film to remove contradictions to the LN scenario would have been done with an optical printer like they used for practically all movies at the time for FX. This would include:

1) Speeding the limo up by removing frames before and after the head shot. Easy peasy.
2) Blackening the back of JFK's head for a few dozen frames. Piece of cake.
3) Cut out the turn onto Elm where the limo barely navigated the turn. Just another splice, which they botched.

So to ans the OP of how long does it take to alter hundreds of frames of film is...a few hours max. Which is exactly what they did. Otherwise, why did they modify it at all?

I already replied to this thread but it got wiped out by the LNers because I was getting too close to home.

This is what I was talking about, delusions of self grandeur are rife in your community.

Any editing done to the film to remove contradictions to the LN scenario would have been done with an optical printer like they used for practically all movies at the time for FX.

This was explained to you in the other thread, as soon as images are combined in an optical printer you have a degraded image with additional layers of grain. The special effects in movies at the time were locked off matte shots or blue screen work and not suitable for Zapruder type alterations.

The following two frames were filmed directly on set but the robots fighting picture was processed with multiple passes through an optical printer for added special effects like lasers and starfields which creates a much softer grainier image whereas the Zapruder film was just exposed once on the correct film stock.




The Zapruder frames reveal no build up of Film grain and thus the film was exposed in Zapruder's camera.

1) Speeding the limo up by removing frames before and after the head shot. Easy peasy.

As soon as even one frame is removed you introduce an obvious stutter but throughout the Zapruder film is silky smooth. In the following gif only one frame was removed and the resulting lack of fluidity is plain to see.

2) Blackening the back of JFK's head for a few dozen frames. Piece of cake.

You do realize that blackening one frame requires the exact correct pigment of black to match the surrounding level of black and then  when you start a series of frames then you have to consider how your black is affected by the movement and constantly changing lightsource that have a direct effect on your black, so in other words without advanced computer cycles to calculate the various intensities of black you're not going to provide anything close to photorealistic.

3) Cut out the turn onto Elm where the limo barely navigated the turn. Just another splice, which they botched.

Or maybe because an 8mm camera only takes a limited amount of film and Zapruder had already used some of the film so was simply saving film for Kennedy.



JohnM

[John Mytton]

I'm a physicist. 

Yeah I thought it was hilarious too, now he's physicist who is also a photogrammetrist on the side.
Too bad all the old posts got scrapped because the list of what professions Trojan magically morphed into to support any number of his arguments was staggering.
He claimed to be a photo something or other expert but didn't know the about the difference in size between 35mm still and motion picture film then he put the sprockets on the wrong side, he tries to bluff his way through but keeps getting busted.



JohnM

[John Mytton]

What are my objectives on this forum, Mytton?

What are your objectives on this forum? What makes you try so hard? What are you trying to accomplish?

"If you're not part of the solution, you're part of the coverup."

Are YOU part of the coverup?

What are my objectives on this forum, Mytton?

To obfuscate as much as possible and make CTs appear to be Paranoid Kooks!

What are your objectives on this forum?

To learn about a time period that is interesting and I like the photo side where you work with a lump of clay and try to create a masterpiece.

What makes you try so hard?

I'm a perfectionist.

What are you trying to accomplish?

To make the World a better Place, and wipe out World War and World Hunger!



JohnM