Nalli confronts Thompson's belief in David Wimp's "blur illusion", that the forward motion between Z312 and Z313 is over-estimated (ie: Thompson thinks the forward movement was half of the two-inches usually claimed).
 Z312 and Z313 |  Z312 and Z312 with horizontal blur to imitate that of Z313 |  Blurred Z312 and Z313 |
It is unusual and educational to have the caliber of a book by Josiah Thompson reviewed by Nicholas Nalli.
(I think the GIF on the right could have had better registration; the back seat and the parade bar aren't matching to the pixel. Aligning those points will slightly draw blurred-Z312 to the left, which would decrease the amount of movement to Kennedy's head, to make it more like two inches.)
Just made this GIF with better-quality frames, applying an horizontal-linear smear filter to Z312, similar to what Nalli did.
Nellie Connally is the only one who seems stationary (Greer's head may move a tiny bit). Mrs. Kennedy moves forward in space (towards the camera), Governor Connally moves upwards and to camera-right, and Kellerman's head moves forwards. These movements of Connally and Kellerman can be seen occurring between Z311 and Z312 and continue smoothly after Z313 (ie: not caused by some sudden braking of the car). Mrs. Kennedy seems to have an immediately reaction to the head shot, maybe ducking her head beginning Z315.
I would guess the forward movement of Kennedy's head in this animation is two inches. Nelli's animation had too much forward movement.
That's a really interesting GIF Jerry, thanks for sharing! It seems to me that the heads of Kellerman and Connally also seem to slightly move forward (although not as much as JFK). Whether this is a function of the Z313 blurring or whether JFK, Connally and Kellerman all moved in that fraction of a second is hard to know.
