Cobra Kai said:

It seems like the technicolor print would be the best reference for color.

Here is a pic of the of the next shot in that scene. I would think the color needs to be close to this.

Even that technicolor print has it's downsides as a reference. First of all, the contrast is way too high. Before rendering my version for Harmy, I tried replicating the technicolor print's contrast, and guess what, whites got crushed and the picture didn't look good. Also, the technicolor print has some tinting here and there. Look at the shadows in this picture for example:

The shadows are a mix of green and yellow here, and the whites are crushed by the high contrast. (or of the exposure of the camera that took this photo?)

And Harmy, correct me if I'm wrong but those shots of Vader and Leia on Tantive IV are not from the movie itself, but production photos. Either way, that guy sure has some nice stuff there. And how he got it? I guess like with all other stuff there's collectors and traders who exchange rare things, even photos.