My understanding is that film would be desaturated by being exposed to light repeatedly (i.e. projection) over time in the same way as if you leave a photo, painting or paint on a wall in direct sunlight. The Technicolor Dye Process may seal the colours better but I don't see how it can make it impervious to light, and when I look at the Technicolor print pictures I can still see a subtle bit of pink. (whether that is copied from the master copy or is fade i dont know). Colour shift is when one of the green, red or blue levels is desaturated more rapidly than the others, leaving the other colours over-represented. So the pink-red shift is when red is over represented as in Gout Star Wars, but to me in Gout ESB it looks blue-tinged as if the blue has been left over-represented.