If your assumption about the (red ?) faded internegative which would have been corrected by one pass was confirmed (and that make sense), it could be interesting to test something : to come back to the original color by crossing the road in the opposite direction.
- Reconstructing the fading (it would be the hardest part and imply a lot of observations and suppositions about the balancing process applied for the Laserdisc)
- Restauring the colors by using your famous tool.