Oh, I think the contrast and brightness of ESB was totally ruined in many shots on the official Blu-rays… just look at how moody and atmospheric (and awesome) the lighting is in echo base in any film-based preservation and compare it to the blu rays. There’s a HUGE difference and the incredible lighting is almost destroyed in many shots.
I don’t think it was the blu-rays, it think it was the SE. I think the blu-ray is a pretty faithful archive of the SE colors, just leaning to too much red/magenta.