Based on what do you figure the blue was added later? The terribly under-saturated laserdisc, or the faded Grindhouse print, which has terrible colors with magenta shadows and green highlights? Or, and this is the least trustworthy of those three super untrustworthy options, your memory from when you were 5 years old?
Towne replied and let me know I’m apparently beating a dead horse (didn’t know this was already a “thang” sorry!)… but I will answer your question since you posed it too me and to do so as intelligently as possible…
Snow and ice… are white. We know this, start there (but of course as they are both highly reflective and thus easily influenced by colored lighting but… now from the laserdisc, which you describe as under-saturated… I agree with that, but looking at Luke’s face hanging upside down in the cave… it’s a good flesh tone… the specular highlights in his face and the yellows in his uniform lets us know there’s plenty of color information in the shot. So if the shot had been made with blue lights, and then the scene desaturated so that the blue disappeared into white, it’s highly unlikely that his face and uniform wouldn’t have been affected in a very unnatural way. Now travelling to the Grindhouse print… again, yes the primary’s are somewhat off… but the snow shows the magenta tones of the faded print. Again… were those snow shots originally not only blue, but a deep blue, the magenta push would made those probably more purplish than simply a gentle magenta hue that’s left (from the obvious pullback color correction since the actual film makes it look absolutely rose colored). And again, the skin tones are “reasonable” to lend that I highly doubt that the blue faded in such a way that when colors were corrected it suddenly went to almost white.
Thing is… I “get” why Lucas changed it. The sun was setting in addition to the snow storm hitting hard (in the story)… Puggo’s film gives it a more “night time” appearance that I think they were going for when they graded that in. There might have also been the artistic choice to make it bluer so that it looks more “alien” to separate Hoth from “Earth”.
But to me in the cave scene, the blue is strong even on Luke’s skin. It doesn’t “feel natural” when I see it.
Thanks for listening. 😃