I spent probably a full day trying to correct this shot for my project, but the blu-ray’s gradients are too degraded for anything more than an approximation regarding color. In particular, the yellow droid’s gradients are crushed in the source to those of C-3PO and the surrounding buildings.
Here’s the above grading (with a slight adjustment) applied to the bluray, using the color correction tool.
Bluray:
Bluray regraded:
Here is the screenshot comparison: