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A Frame Tracing Study of the Zapruder Film

Robert S. Fritzius - Shade Tree Physics

Installed 06 Nov 2013. Latest Update 28 Oct 2017. Text changes or modifications are in bold.

The Warren Commission investigaton into the Assassination of John F. Kennedy used enlarged printed black-and-white frames from the Abraham Zapruder Dealey Plaza film as an aid in their investigation. The frames, labeled in numerical sequence, were provided to the commission by the Federal Bureau of Investigation. These were published in Volume XVIII of the commission's hearing.(1)

Here is a line drawing mosaic of the Zapruder film, from frame 171 to 334. It was made from rapidograph ink tracings on acetate overlays of salient elements in the black-and-white frames. (The acetate frame tracings were made in about 1984.) The tracings were scanned into gif files in November 2013 and were then superimposed onto each other to make the mosaic. In each tracing a dot was drawn to represent center-of-frame. By following these dots one can see where Zapruder was aiming his camera. Presently the tracings are mostly for every fifth frame. Areas of particular interest are enclosed in red inset-frames.


Dealey Plaza mosaic
Dealey Plaza Mosaic


This mosaic was created, in part, to look for jerky motions of Zapruder's camera in response to gunshots. One possible such motion exists between frames 313 and 314. In this mosaic region the average number of pixels between frames (for frames 303 to 315) is 25, with a standard deviation of approximately 10 pixels. (This uses some creative accounting for frames 303 to 311 where, at present, I only have tracings for every other frame. The positions of the centerpoints for the intermmediate frames are interpolated.) Between frames 313 and 314 the number of pixels is 45. (That's approximately two standard deviations above the mean.) Zapruder said that it seemed like he heard a shot "from behind me".(2) What looks like a jerk to-the-right on the film may be evidence that a shot associated with frame 313 came from Zapruder's right.

There is a prominent downward zig-zag in Zapruder's camera pointing between frames 329 and 333.

See the refined Zapruder Stabilized Motion Panorama.(3) In it you can see where Zapruder begins to tilt his camera to about three degrees to the right as the limo moves out of view of the Stemmons freeway sign. It appears that Zapruder began using the roadway curb as his horizontal reference.

References

(1) Warren Commission Hearings, Volume XVIII, CE 885 - Album of black and white photographs of frames from the Zapruder, Nix, and Muchmore films. (Frames 171-334 of the Zapruder film were used.) - Digitized copies of these frames are available online at the Assassination Archives and Research Center. - Frame pairs from Zapruder's film start with frames 171 and 172

(2) Testimony of Abraham Zapruder, Hearings Before the President's Commission on the Assassination of President Kennedy (the Warren Commission) Volume VII, page 569.



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