Beware that the Extended Edition is that way because they messed with, actually messed up, the colors. When processed in my trusty paint program, you can see crushed colors that no longer have any information in them (original screen-cap is from the Blu-ray movie review website):

Here, any R-G-B-separation plane’s “0”-value pixels are inverted to “255” to make them stand out for examination. Note that only Red is crushed in this picture. Also, the black boarder, at 0-0-0, becomes 255-255-255.

Any color correction will suffer because of these wiped-out areas. For a proper color correction, those crushed areas must from recreated from other separation plane(s) that are not crushed in those areas. This procedure is demonstrated in The Wizard Of Oz restoration documentary (I added code to the link to start it at this appropriate playback time):
YouTube - Prettier Than Ever: Restoration of The Wizard of Oz