The transfer from film to VHS way back in 77-78 was accomplished by a method that looks very much like time-compression. A good analogy would be transferring 24p film to 59.94i video by projecting the film on a wall at 24 frames per second and recording it with an NTSC video camera at 59.94 fields per second.
This process results in each and every frame being an average of several of its temporal neighbors.
In consequence, bright->dark shot-changes are blown-out and dark->bright shot-changes are crushed for the first few frames until the “average” events out to the overall brightness of the shot. Rinse, repeat.
Does this make any sense?
EDIT: Also, some shot-changes just go crazy. I imagine that this is due to the automatic gain circuitry in the VCR used to make the copy (remember: this tape is 2nd gen) from the master.
Do you know how this tape was made? Apologies if I missed the specific explanation somewhere. Anyways, if someone simply pointed their vhs video camera at the projected screen, you might have had things like auto exposure, auto white balance come into play.
Also, could you repost what was your equipment used again? Or a link to a picture, pictures referenced no longer show up. Like on page 6 you mentioned having a tv tuner. Was this a digital capture to a computer or a straight copy to a dvd recorder? (or both?) You mentioned using virtual dub (computer program) and also a Panasonic ES-10 (dvd recorder).
Interestingly I almost purchased a ES-10 last winter but went with a EA-18 because the 10 didn’t have a firewire input and advice in the videohelp forum mentioned it didn’t quite have full resolution (704/480 vs 720x480). I was also told the ES-10 had automatic DNR that could not be turned off during recording.